The Enzyme Database

Your query returned 3 entries.    printer_iconPrintable version



EC 1.20.4.2     
Accepted name: methylarsonate reductase
Reaction: methylarsonate + 2 glutathione = methylarsonite + glutathione disulfide + H2O
For diagram of arsenate catabolism, click here
Glossary: methylarsonite = methylarsonous acid
cacodylic acid = dimethylarsinic acid
Other name(s): MMA(V) reductase
Systematic name: methylarsonate:glutathione oxidoreductase
Comments: The product, methylarsonite, is biologically methylated by EC 2.1.1.137, arsenite methyltransferase, to form cacodylic acid.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, UM-BBD, CAS registry number: 254889-62-8
References:
1.  Zakharyan, R.A. and Aposhian, H.V. Enzymatic reduction of arsenic compounds in mammalian systems: the rate-limiting enzyme of rabbit liver arsenic biotransformation is MMA(V) reductase. Chem. Res. Toxicol. 12 (1999) 1278–1283. [DOI] [PMID: 10604879]
[EC 1.20.4.2 created 2000 as EC 1.97.1.7, transferred 2001 to EC 1.20.4.2, modified 2003]
 
 
EC 2.1.1.137     
Accepted name: arsenite methyltransferase
Reaction: (1) S-adenosyl-L-methionine + arsenite = S-adenosyl-L-homocysteine + methylarsonate
(2) S-adenosyl-L-methionine + methylarsonite = S-adenosyl-L-homocysteine + dimethylarsinate
For diagram of arsenate catabolism, click here
Other name(s): S-adenosyl-L-methionine:arsenic(III) methyltransferase; S-adenosyl-L-methionine:methylarsonite As-methyltransferase; methylarsonite methyltransferase
Systematic name: S-adenosyl-L-methionine:arsenite As-methyltransferase
Comments: An enzyme of the biotransformation pathway that forms dimethylarsinate from inorganic arsenite and arsenate. It methylates arsenite to form methylarsonate, Me-AsO3H2, which is reduced by EC 1.20.4.2, methylarsonate reductase, to methylarsonite, Me-As(OH)2. Methylarsonite is also a substrate for this enzyme (EC 2.1.1.137), which converts it into the much less toxic compound dimethylarsinate (cacodylate), Me2As(O)-OH.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, UM-BBD, CAS registry number: 167140-41-2
References:
1.  Zakharyan, R.A. and Aposhian, H.V. Enzymatic reduction of arsenic compounds in mammalian systems: the rate-limiting enzyme of rabbit liver arsenic biotransformation is MMA(V) reductase. Chem. Res. Toxicol. 12 (1999) 1278–1283. [DOI] [PMID: 10604879]
2.  Zakharyan, R.A., Ayala-Fierro, F., Cullen, W.R., Carter, D.M. and Aposhian, H.V. Enzymatic methylation of arsenic compounds. VII. Monomethylarsonous acid (MMAIII) is the substrate for MMA methyltransferase of rabbit liver and human hepatocytes. Toxicol. Appl. Pharmacol. 158 (1999) 9–15. [DOI] [PMID: 10387927]
3.  Zakharyan, R.A., Wildfang, E. and Aposhian, H.V. Enzymatic methylation of arsenic compounds. III. The marmoset and tamarin, but not the rhesus, monkeys are deficient in methyltransferases that methylate inorganic arsenic. Toxicol. Appl. Pharmacol. 140 (1996) 77–84. [DOI] [PMID: 8806872]
4.  Zakharyan, R.A., Wu, Y., Bogdan, G.M. and Aposhian, H.V. Enzymatic methylation of arsenic compounds: assay, partial purification, and properties of arsenite methyltransferase and monomethylarsonic acid methyltransferase of rabbit liver. Chem. Res. Toxicol. 8 (1995) 1029–1038. [PMID: 8605285]
5.  Lin, S., Shi, Q., Nix, F.B., Styblo, M., Beck, M.A., Herbin-Davis, K.M., Hall, L.L., Simeonsson, J.B. and Thomas, D.J. A novel S-adenosyl-L-methionine:arsenic(III) methyltransferase from rat liver cytosol. J. Biol. Chem. 277 (2002) 10795–10803. [DOI] [PMID: 11790780]
[EC 2.1.1.137 created 2000, (EC 2.1.1.138 incorporated 2003), modified 2003]
 
 
EC 2.1.1.138      
Deleted entry:  methylarsonite methyltransferase. Reaction due to EC 2.1.1.137, arsonite methyltransferase
[EC 2.1.1.138 created 2000, deleted 2003]
 
 


Data © 2001–2020 IUBMB
Web site © 2005–2020 Andrew McDonald