Cloned (Comment) | Organism |
---|---|
expressed in Escherichia coli | Astragalus bisulcatus |
Protein Variants | Comment | Organism |
---|---|---|
A184T | mutant enzyme gains the ability to methylate L-homocysteine | Astragalus bisulcatus |
additional information | the but lacks the selenocysteine methyltransferase activity in vitro, explaining why little or no detectable levels of Se-methylselenocysteine accumulation are observed in the non-accumulator plant. Sequence analysis reveals that the selenocysteine methyltransferase from all plant that accumulate selenium contain a glycine residue at position 24, whereas the plants that do not accumulate selenium possess an alanine residue. A phenylalanine residue at position 148 in the accumulator selenocysteine methyltransferases is replaced by a tyrosine residue in non-accumulators. Thr334 is common among the Se accumulator species is lacking in the non-accumulator selenocysteine methyltransferase sequences and it appears as a complete deletion of the Thr334 codon of the DNA sequence | Astragalus bisulcatus |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
0.37 | - |
L-selenocysteine | wild-type enzyme | Astragalus bisulcatus | |
0.46 | - |
L-selenocysteine | mutant enzyme A184T | Astragalus bisulcatus | |
0.74 | - |
L-homocysteine | mutant enzyme A184T, wild-type enzyme is not active with L-homocysteine | Astragalus bisulcatus |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
chloroplast | predominantly localized within | Astragalus bisulcatus | 9507 | - |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Astragalus bisulcatus | P56707 | - |
- |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
leaf | - |
Astragalus bisulcatus | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
S-adenosyl-L-methionine + L-homocysteine | no activity with wild-type enzyme. A184T mutant enzyme gains the ability to methylate L-homocysteine | Astragalus bisulcatus | S-adenosyl-L-homocysteine + L-methionine | - |
? | |
S-adenosyl-L-methionine + L-selenocysteine | - |
Astragalus bisulcatus | S-adenosyl-L-homocysteine + Se-methyl-L-selenocysteine | - |
? |
Synonyms | Comment | Organism |
---|---|---|
selenocysteine methyltransferase | - |
Astragalus bisulcatus |
SMT | - |
Astragalus bisulcatus |