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Literature summary extracted from
- The trans-membrane cytochrome b561 proteins structural information and biological function (2014), Curr. Protein Pept. Sci., 15, 745-760 .
Cloned(Commentary)
| EC Number | Cloned (Comment) | Organism |
|---|---|---|
| 7.2.1.3 | cloning and recombinant expression of untagged four CYB561 isoforms in yeast YPH499 cells, recombinant expression of two C-terminally His10- or Strep-II-tagged CYB561 paralogues in either Escherichia coli or in Pichia pastoris. Functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity | Arabidopsis thaliana |
| 7.2.1.3 | functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 deficient in ferric reductase activity | Zea mays |
| 7.2.1.3 | functional expression of the enzyme in Saccharomyces cerevisiae strain S288C DELTAfre1DELTAfre2 which is deficient in ferric reductase activity | Schistosoma japonicum |
| 7.2.1.3 | recombinant expression of C-terminally His6-tagged isozyme CGCytb in Spodoptera frugiperda Sf9 cells as well as in Pichia pastoris strain GS115, and recombinant expression of C-terminally His6-tagged isozyme CGCytb in Escherichia coli | Bos taurus |
| 7.2.1.3 | recombinant expression of C-terminally His6-tagged isozyme DCytb in Spodoptera frugiperda Sf9 cells, untagged, apoform or fully functional isozyme DCytb in Escherichia coli | Homo sapiens |
| 7.2.1.3 | recombinant expression of C-terminaly His6-tagged enzyme in yeast YPH499 cells, recombinant expression of C-terminally His6-tagged isozyme DCytb in Escherichia coli | Mus musculus |
Protein Variants
| EC Number | Protein Variants | Comment | Organism |
|---|---|---|---|
| 7.2.1.3 | E79A | site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center | Bos taurus |
| 7.2.1.3 | H108A | site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility | Mus musculus |
| 7.2.1.3 | H117A | site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb | Arabidopsis thaliana |
| 7.2.1.3 | H120A | site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes | Homo sapiens |
| 7.2.1.3 | H120A | site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb | Mus musculus |
| 7.2.1.3 | H156A | site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb | Arabidopsis thaliana |
| 7.2.1.3 | H159A | site-directed mutagenesis of DCytb, the mutation results in partial loss of hemes | Homo sapiens |
| 7.2.1.3 | H159A | site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility | Mus musculus |
| 7.2.1.3 | H33A | site-directed mutagenesis, mutation in human DCytb does not influence the physicochemical properties of protein as compared to the wild-type | Homo sapiens |
| 7.2.1.3 | H50A | site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes | Homo sapiens |
| 7.2.1.3 | H50A | site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb | Arabidopsis thaliana |
| 7.2.1.3 | H50A/H120A | site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb | Homo sapiens |
| 7.2.1.3 | H52A | site-directed mutagenesis, the mutation results in nearly undetectable levels of rCGCytb | Mus musculus |
| 7.2.1.3 | H83A | site-directed mutagenesis, no alteration is found from the ascorbate reducibility compared to mouse wild-type rCGCytb | Mus musculus |
| 7.2.1.3 | H83A | site-directed mutagenesis, the mutation leads to reduced reduction of ascorbate by the mutant TCytb | Arabidopsis thaliana |
| 7.2.1.3 | H83A/H156A | site-directed mutagenesis | Arabidopsis thaliana |
| 7.2.1.3 | H83L/H156L | site-directed mutagenesis | Arabidopsis thaliana |
| 7.2.1.3 | H86A | site-directed mutagenesis of DCytb, the mutation results in complete loss of hemes | Homo sapiens |
| 7.2.1.3 | H86A | site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility | Mus musculus |
| 7.2.1.3 | H86A/H159A | site-directed mutagenesis of DCytb, the mutant contains one heme-b per double His-mutant rDCytb | Homo sapiens |
| 7.2.1.3 | H86A/H159A | site-directed mutagenesis, the mutation results in a practically unchanged level of protein expression and a considerably lower ascorbate reducibility | Mus musculus |
| 7.2.1.3 | K81A/R150A/F105W/H106E | site-directed mutagenesis, the quadruple mutation completely prevents ascorbate from reducing the protein, inactive mutant | Arabidopsis thaliana |
| 7.2.1.3 | K83A | site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type | Zea mays |
| 7.2.1.3 | K83D | site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type | Zea mays |
| 7.2.1.3 | K83E | site-directed mutagenesis, the mutant shows reduced ascorbate reducibility compared to wild-type | Zea mays |
| 7.2.1.3 | additional information | replacing any of the 4 highly conserved His residues, coordinating the two b-type hemes, by Ala in mouse rLCytb completely abolishes the transmembrane ferric reductase activity of rLCytb. Midpoint ascorbate concentration for the reduction of low-potential heme-b centers is hardly influenced by the R74X replacements but that for the high-potential heme-b centers show a significant trend | Mus musculus |
| 7.2.1.3 | N78K | site-directed mutagenesis, the mutation in bovine rCGCytb does not influence the physicochemical properties of protein as compared to the wild-type | Bos taurus |
| 7.2.1.3 | R72A | site-directed mutagenesis, the mutant shows reduced activity compared to wild-type | Mus musculus |
| 7.2.1.3 | R72E | site-directed mutagenesis, the mutant shows reduced activity compared to wild-type | Mus musculus |
| 7.2.1.3 | R72E | site-directed mutagenesis, the mutation of TCytb does not affect the final reduction level of rTCytb by ascorbate but results in a complete loss of the pH-dependent initial time-lag upon electron acceptance from ascorbate | Mus musculus |
| 7.2.1.3 | R72K | site-directed mutagenesis, the mutant shows reduced activity compared to wild-type | Mus musculus |
| 7.2.1.3 | R72T | site-directed mutagenesis, the mutant shows reduced activity compared to wild-type | Mus musculus |
| 7.2.1.3 | R72Y | site-directed mutagenesis, the mutant shows reduced activity compared to wild-type | Mus musculus |
| 7.2.1.3 | S118A | site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type | Zea mays |
| 7.2.1.3 | T84A | site-directed mutagenesis, the mutation in bovine rCGCytb causes significant (but no extreme) alteration in at least one of the two (sometimes three) midpoint ascorbate concentrations characterizing the redox transition of hemes-b, and the mutation does not block the reduction of either heme-b center | Bos taurus |
| 7.2.1.3 | W122A | site-directed mutagenesis, mutation in maize TCytb does not influence the physicochemical properties of protein as compared to the wild-type | Zea mays |
Localization
| EC Number | Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|---|
| 7.2.1.3 | brush border | of duodenal mucosa | Mus musculus | 5903 | - |
| 7.2.1.3 | chromaffin granule membrane | CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins | Bos taurus | 42584 | - |
| 7.2.1.3 | chromaffin granule membrane | CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins | Mus musculus | 42584 | - |
| 7.2.1.3 | chromaffin granule membrane | CGCytb, the chromaffin granule CYB561 of the mammalian adrenal glands (CGCytb) makes up about 10-15% of the adrenal gland chromaffin granule membrane proteins | Homo sapiens | 42584 | - |
| 7.2.1.3 | lysosome | LCytb | Bos taurus | 5764 | - |
| 7.2.1.3 | lysosome | LCytb | Mus musculus | 5764 | - |
| 7.2.1.3 | lysosome | LCytb | Homo sapiens | 5764 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane | Schistosoma japonicum | 16020 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six trans-membrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling | Arabidopsis thaliana | 16020 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, in the vacuolar (tonoplast) membrane. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling | Zea mays | 16020 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a trans-membrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling | Bos taurus | 16020 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling | Mus musculus | 16020 | - |
| 7.2.1.3 | membrane | a transmembrane enzyme, localization of both the N- and C-termini of CGCytb in the cytoplasm. Native CGCytb is a transmembrane electron transferring protein that has 6 transmembrane domains with two pairs of His residues, arranged on four consecutive transmembrane domains (the CYB561-core), for coordinating two b-type hemes, one on each side of the membrane, transmembrane orientation, modeling | Homo sapiens | 16020 | - |
| 7.2.1.3 | microsome | - |
Bos taurus | - |
- |
| 7.2.1.3 | tonoplast | TCytb | Arabidopsis thaliana | - |
- |
| 7.2.1.3 | tonoplast | TCytb | Zea mays | - |
- |
| 7.2.1.3 | vacuolar membrane | TCytb | Arabidopsis thaliana | 5774 | - |
| 7.2.1.3 | vacuolar membrane | TCytb | Zea mays | 5774 | - |
Natural Substrates/ Products (Substrates)
| EC Number | Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Arabidopsis thaliana | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? |  |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Bos taurus | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Mus musculus | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Zea mays | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Homo sapiens | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | Schistosoma japonicum | - |
monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | additional information | Schistosoma japonicum | a few members of the CYB561 protein family function as ferric reductases in vivo | ? | - |
? | |
| 7.2.1.3 | additional information | Bos taurus | trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb | ? | - |
? | |
Organism
| EC Number | Organism | UniProt | Comment | Textmining |
|---|---|---|---|---|
| 7.2.1.3 | Arabidopsis thaliana | Q9SWS1 | four CYB561 isoforms | - |
| 7.2.1.3 | Bos taurus | P10897 | - |
- |
| 7.2.1.3 | Homo sapiens | P49447 | - |
- |
| 7.2.1.3 | Mus musculus | Q6P1H1 | LCytb | - |
| 7.2.1.3 | Schistosoma japonicum | Q5D8X4 | - |
- |
| 7.2.1.3 | Zea mays | Q6I681 | - |
- |
Posttranslational Modification
| EC Number | Posttranslational Modification | Comment | Organism |
|---|---|---|---|
| 7.2.1.3 | acetylation | the N-terminus of isozyme CBCytB is anchored to the membrane by acetylation of the amino-terminal Met residue | Bos taurus |
Purification (Commentary)
| EC Number | Purification (Comment) | Organism |
|---|---|---|
| 7.2.1.3 | native chromaffin granule CYB561 from adrenal gland from the chromaffin granule membrane by Triton X-100 solubilzation and separation of the solubilized nCGCytb by preparative electrophoresis. Recombinant C-terminaly His6-tagged isozyme CGCytb from Spodoptera frugiperda Sf9 cells, Pichia pastoris strain GS115, or Escherichia coli by nickel affinity chromatography to homogeneity | Bos taurus |
| 7.2.1.3 | recombinant C-terminally His6-tagged isozyme DCytb from Spodoptera frugiperda Sf9 cells, and untagged, apoform or fully functional isozyme DCytb from Escherichia coli, to homogeneity | Homo sapiens |
| 7.2.1.3 | recombinant C-terminaly His6-tagged enzyme from yeast YPH499 cells by nickel affinity chromatography, recombinant C-terminally His6-tagged isozyme DCytb from Escherichia coli | Mus musculus |
| 7.2.1.3 | recombinant untagged four CYB561 isoforms from yeast YPH499 cells partially, two recombinant C-terminally His10- or Strep-II-tagged CYB561 paralogues from Escherichia coli and Pichia pastoris by affinity chromatography | Arabidopsis thaliana |
Reaction
| EC Number | Reaction | Comment | Organism | Reaction ID |
|---|---|---|---|---|
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Arabidopsis thaliana | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Bos taurus | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Mus musculus | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Zea mays | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Homo sapiens | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] = monodehydroascorbate[side 1] + Fe(II)[side 2] | reaction mechanism | Schistosoma japonicum |
Source Tissue
| EC Number | Source Tissue | Comment | Organism | Textmining |
|---|---|---|---|---|
| 7.2.1.3 | adrenal gland | - |
Bos taurus | - |
| 7.2.1.3 | adrenal gland | - |
Mus musculus | - |
| 7.2.1.3 | adrenal gland | - |
Homo sapiens | - |
| 7.2.1.3 | duodenal mucosa | brush-border membrane, DCytb | Mus musculus | - |
| 7.2.1.3 | macrophage | - |
Bos taurus | - |
| 7.2.1.3 | macrophage | - |
Mus musculus | - |
| 7.2.1.3 | macrophage | - |
Homo sapiens | - |
| 7.2.1.3 | additional information | the parasitic trematode Schistosoma japonicum contains a CYB561 protein localized to the schistosome tegument | Schistosoma japonicum | - |
Substrates and Products (Substrate)
| EC Number | Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|---|
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Arabidopsis thaliana | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Bos taurus | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Mus musculus | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Zea mays | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Homo sapiens | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | ascorbate[side 1] + Fe(III)[side 2] | - |
Schistosoma japonicum | monodehydroascorbate[side 1] + Fe(II)[side 2] | - |
? | |
| 7.2.1.3 | additional information | structure-function relationship, overview | Arabidopsis thaliana | ? | - |
? | |
| 7.2.1.3 | additional information | structure-function relationship, overview | Zea mays | ? | - |
? | |
| 7.2.1.3 | additional information | structure-function relationship, overview | Schistosoma japonicum | ? | - |
? | |
| 7.2.1.3 | additional information | a few members of the CYB561 protein family function as ferric reductases in vivo | Schistosoma japonicum | ? | - |
? | |
| 7.2.1.3 | additional information | trans-membrane ferric reductase activity is also demonstrated in a reconstituted proteoliposome system with ascorbate as the electron donor inside the liposomes, recombinant CGCytb as trans-membrane electron carrier, and ferricyanide as the electron acceptor outside the liposomes. A few members of the CYB561 protein family function as ferric reductases in vivo. The other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb | Bos taurus | ? | - |
? | |
| 7.2.1.3 | additional information | enzyme assays also with purified chromaffin granule membrane ghosts, or purified proteins in detergent micelles, or in reconstituted membrane vesicles. Structure-function relationship, overview | Bos taurus | ? | - |
? | |
| 7.2.1.3 | additional information | the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview | Mus musculus | ? | - |
? | |
| 7.2.1.3 | additional information | the other heme-b center is responsible for the ascorbate oxidation by iozyme CGCytb. Structure-function relationship, overview | Homo sapiens | ? | - |
? | |
Subunits
| EC Number | Subunits | Comment | Organism |
|---|---|---|---|
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Arabidopsis thaliana |
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Bos taurus |
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Mus musculus |
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Zea mays |
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Homo sapiens |
| 7.2.1.3 | More | Cytb561 enzyme structure analysis, structure-function relationship, detailed overview | Schistosoma japonicum |
Synonyms
| EC Number | Synonyms | Comment | Organism |
|---|---|---|---|
| 7.2.1.3 | CGCytb | - |
Bos taurus |
| 7.2.1.3 | CGCytb | - |
Mus musculus |
| 7.2.1.3 | CGCytb | - |
Homo sapiens |
| 7.2.1.3 | chromaffin granule CYB561 | - |
Bos taurus |
| 7.2.1.3 | chromaffin granule CYB561 | - |
Mus musculus |
| 7.2.1.3 | chromaffin granule CYB561 | - |
Homo sapiens |
| 7.2.1.3 | chromomembrin B | - |
Bos taurus |
| 7.2.1.3 | CYB561 | - |
Arabidopsis thaliana |
| 7.2.1.3 | CYB561 | - |
Bos taurus |
| 7.2.1.3 | CYB561 | - |
Mus musculus |
| 7.2.1.3 | CYB561 | - |
Zea mays |
| 7.2.1.3 | CYB561 | - |
Homo sapiens |
| 7.2.1.3 | CYB561 | - |
Schistosoma japonicum |
| 7.2.1.3 | cytochrome b-559 | - |
Bos taurus |
| 7.2.1.3 | cytochrome b561 | - |
Bos taurus |
| 7.2.1.3 | DCytb | - |
Mus musculus |
| 7.2.1.3 | DCytb | - |
Homo sapiens |
| 7.2.1.3 | ferric chelate reductase | - |
Schistosoma japonicum |
| 7.2.1.3 | LCytb | - |
Bos taurus |
| 7.2.1.3 | LCytb | - |
Mus musculus |
| 7.2.1.3 | LCytb | - |
Homo sapiens |
| 7.2.1.3 | TCytb | - |
Arabidopsis thaliana |
| 7.2.1.3 | TCytb | - |
Zea mays |
| 7.2.1.3 | trans-membrane ferric-chelate reductase | - |
Mus musculus |
pH Optimum
| EC Number | pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|---|
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Arabidopsis thaliana |
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Bos taurus |
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Mus musculus |
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Zea mays |
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Homo sapiens |
| 7.2.1.3 | additional information | - |
the rate of reduction of CYB561 by ascorbate is only slightly pH-dependent, steady-state reduction kinetics | Schistosoma japonicum |
Cofactor
| EC Number | Cofactor | Comment | Organism | Structure |
|---|---|---|---|---|
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Arabidopsis thaliana | |
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Bos taurus | |
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Mus musculus | |
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Zea mays | |
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Homo sapiens | |
| 7.2.1.3 | ascorbate | cytosolic ascorbate is the cellular electron donor for the CYB561 proteins | Schistosoma japonicum | |
| 7.2.1.3 | cytochrome b561 | a CYB561 protein | Arabidopsis thaliana | |
| 7.2.1.3 | cytochrome b561 | a CYB561 protein | Mus musculus | |
| 7.2.1.3 | cytochrome b561 | a CYB561 protein | Zea mays | |
| 7.2.1.3 | cytochrome b561 | a CYB561 protein | Homo sapiens | |
| 7.2.1.3 | cytochrome b561 | a CYB561 protein | Schistosoma japonicum | |
| 7.2.1.3 | heme b | two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials of heme b, comparisons | Schistosoma japonicum | |
| 7.2.1.3 | heme b | two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons | Mus musculus | |
| 7.2.1.3 | heme b | two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons | Zea mays | |
| 7.2.1.3 | heme b | two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons | Homo sapiens | |
| 7.2.1.3 | heme b | two heme-b centers and CYB561 protein, structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b, characterized with a low-spin EPR signal in the vicinity of gz = 3.1, is located on the cytosolic side of the protein | Arabidopsis thaliana | |
| 7.2.1.3 | heme b | two heme-b centers are coordinated by two pairs of His residues localized in the central four transmembrane domains, probably very close to the membrane interface. The midpoint redox potentials of the two hemes are above 0 mV and about 100 mV apart from each other. CYB561 protein structure analysis and comparisons, overview. Midpoint redox potentials, spin, and spectra of heme b, comparisons. The high-potential heme-b center of CGCytb is located on the cytosolic side of the protein, mutational analysis | Bos taurus | |
| 7.2.1.3 | additional information | neither ferrocyanide nor durohydroquinone can reduce nCGCytb | Bos taurus | |
| 7.2.1.3 | additional information | neither ferrocyanide nor durohydroquinone can reduce nCGCytb | Mus musculus |
General Information
| EC Number | General Information | Comment | Organism |
|---|---|---|---|
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Arabidopsis thaliana |
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Bos taurus |
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Mus musculus |
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Zea mays |
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Homo sapiens |
| 7.2.1.3 | evolution | the enzyme is a member of the CYB561 protein family | Schistosoma japonicum |
| 7.2.1.3 | malfunction | mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins | Arabidopsis thaliana |
| 7.2.1.3 | malfunction | mutation of His residues coordinating the intra-vesicular-side heme-b results in an almost complete loss of protein, while mutation of His residues coordinating the cytosolic-side heme-b hardly affects the expression of CYB561 proteins but results in a changed reducibility and heme content of these proteins. Replacing any of the 4 highly conserved His residues, coordinating the two b-type hemes, by Ala in mouse rLCytb completely abolishes the transmembrane ferric reductase activity of rLCytb | Mus musculus |
| 7.2.1.3 | additional information | cytochrome b561 (CYB561) proteins are ascorbate reducible, transmembrane proteins consisting of 200-300 amino acids, about half of which are hydrophobic. CYB561 proteins have six transmembrane helices and two b-type hemes, one on each side of the membrane. The two heme-b centers are coordinated by two pairs of His residues localized in the central four transmembrane domains, probably very close to the membrane interface. The midpoint redox potentials of the two hemes are above 0 mV and about 100 mV apart from each other. The binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb | Bos taurus |
| 7.2.1.3 | additional information | the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that are inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview | Schistosoma japonicum |
| 7.2.1.3 | additional information | the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview | Zea mays |
| 7.2.1.3 | additional information | the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb | Mus musculus |
| 7.2.1.3 | additional information | the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. Importance of an Arg residue in the reduction of rCGCytb | Homo sapiens |
| 7.2.1.3 | additional information | the binding sites for the ascorbate on the cytoplasmic and the monodehydroascorbate on the non-cytoplasmic side do not correspond to the putative binding sites that had been inferred from the sequence (homology) analysis as well as from site directed mutagenesis of a number of CYB561 proteins. Models for the sidedness of CYB561 enzymes and the reduction by ascorbate, overview. The amino acid side chains contributing to the docking of ascorbate on the cytoplasmic surface of the crystallized protein (K77, K81, Y140, R150 and A151) do not constitute a single contiguous region but originate at distant locations of the primary sequence of the protein | Arabidopsis thaliana |
| 7.2.1.3 | physiological function | b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport | Bos taurus |
| 7.2.1.3 | physiological function | b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells | Mus musculus |
| 7.2.1.3 | physiological function | b-type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Isozyme DCytb is capable of reducing ferric chelates and plays an important role in the iron acquisition of cells | Homo sapiens |
| 7.2.1.3 | physiological function | b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system | Arabidopsis thaliana |
| 7.2.1.3 | physiological function | b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. Plant rTCytb are capable of transporting electrons from cytosolic ASC to extracellular ferric chelates (ferricyanide, ferric-EDTA) in a yeast model system | Zea mays |
| 7.2.1.3 | physiological function | b-Type cytochromes are heme-containing, electron-transporting proteins in which the redox active center(s) is (are) iron-protoporphyrin(s) IX non-covalently bound to the protein matrix. Some of the b-type cytochromes are localized in membranous structures and have two heme-b prosthetic groups, the major function of these proteins is transmembrane electron transport. The parasitic trematode Schistosoma japonicum contains a CYB561 protein with ferric chelate reductase activity and localizes to the schistosome tegument, the enzyme might be responsible for iron acquisition in the parasite | Schistosoma japonicum |
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Release 2023.1 (January 2023)
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