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Literature summary for 4.2.1.1 extracted from

  • Mikulski, R.; Avvaru, B.S.; Tu, C.; Case, N.; McKenna, R.; Silverman, D.N.
    Kinetic and crystallographic studies of the role of tyrosine 7 in the active site of human carbonic anhydrase II (2011), Arch. Biochem. Biophys., 506, 181-187.
    View publication on PubMedView publication on EuropePMC
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Protein Variants

Protein Variants Comment Organism
additional information replacement of Tyr7 with eight other amino acids has no effect on the interconversion of bicarbonate and CO2, but in some cases causes enhancements in the rate constant of proton transfer by nearly 10fold. Mutant variants at position 7 show a melting temperature approximately 8°C lower than that of the wild-type enzyme Homo sapiens
Y7A site-directed mutagenesis Homo sapiens
Y7D site-directed mutagenesis Homo sapiens
Y7F site-directed mutagenesis Homo sapiens
Y7I site-directed mutagenesis, replacement of Tyr7 with Ile has no effect on the interconversion of bicarbonate and CO2, but enhances intramolecular proton transfer approximately twofold. No changes occur in the ordered solvent structure in the active-site cavity or in the conformation of the side chain of the proton shuttle His64, while the first 11 residues of the amino-terminal chain in Y7I HCA II assume an alternate conformation compared to the wild-type enzyme Homo sapiens
Y7N site-directed mutagenesis Homo sapiens
Y7R site-directed mutagenesis Homo sapiens
Y7S site-directed mutagenesis Homo sapiens
Y7W site-directed mutagenesis Homo sapiens

Metals/Ions

Metals/Ions Comment Organism Structure
Zn2+ required. The side chain of Tyr7 in HCA II extends into the active-site cavity about 7 A from the catalytic zinc atom Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
H2CO3 Homo sapiens
-
 CO2 + H2O
-
 r

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Reaction

Reaction Comment Organism Reaction ID
H2CO3 = CO2 + H2O the rate limiting step in catalysis of bicarbonate dehydration by HCA II is an intramolecular proton transfer from His64 to the zinc-bound hydroxide Homo sapiens
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
H2CO3
-
 Homo sapiens CO2 + H2O
-
 r
additional information the enzyme also shows esterase activity in 4-nitrophenylacetate hydrolysis Homo sapiens ?
-
 ?

Synonyms

Synonyms Comment Organism
carbonic anhydrase II
-
 Homo sapiens
HCA II
-
 Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
 assay at Homo sapiens

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
8
-
 assay at Homo sapiens

pH Range

pH Minimum pH Maximum Comment Organism
additional information
-
 pH profiles for the hydration of CO2 catalyzed by wild-type HCA II and mutant Y7I HCA II, overview Homo sapiens

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
additional information
-
 additional information Km/kcat values for 4-nitrophenylacetate hydrolysis by wild-type and mutant enzymes, overview Homo sapiens