Arsenite methyltransferase

Arsenite methyltransferase (EC 2.1.1.137, S-adenosyl-L-methionine:arsenic(III) methyltransferase, S-adenosyl-L-methionine:methylarsonite As-methyltransferase, methylarsonite methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:arsenite As-methyltransferase.^[1]^[2]^[3]^[4]^[5] This enzyme catalyses the following chemical reaction

(1) S-adenosyl-L-methionine + arsenite

\rightleftharpoons

S-adenosyl-L-homocysteine + methylarsonate

(2) S-adenosyl-L-methionine + methylarsonite

\rightleftharpoons

S-adenosyl-L-homocysteine + dimethylarsinate

An enzyme of the biotransformation pathway that forms dimethylarsinate from inorganic arsenite and arsenate.

References

↑ Zakharyan, R.A. and Aposhian, H.V. (1999). "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 (12): 1278–1283. doi:10.1021/tx9901231. PMID 10604879.
↑ Zakharyan, R.A., Ayala-Fierro, F., Cullen, W.R., Carter, D.M. and Aposhian, H.V. (1999). "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 (1): 9–15. doi:10.1006/taap.1999.8687. PMID 10387927.
↑ Zakharyan, R.A., Wildfang, E. and Aposhian, H.V. (1996). "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 (1): 77–84. doi:10.1006/taap.1996.0199. PMID 8806872.
↑ Zakharyan, R.A., Wu, Y., Bogdan, G.M. and Aposhian, H.V. (1995). "Enzymatic methylation of arsenic compounds: assay, partial purification, and properties of arsenite methyltransferase and monomethylarsonic acid methyltransferase of rabbit liver". Chem. Res. Toxicol. 8 (8): 1029–1038. doi:10.1021/tx00050a006. PMID 8605285.
↑ 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. (2002). "A novel S-adenosyl-L-methionine:arsenic(III) methyltransferase from rat liver cytosol". J. Biol. Chem. 277 (13): 10795–10803. doi:10.1074/jbc.M110246200. PMID 11790780.

External links

Arsenite methyltransferase at the US National Library of Medicine Medical Subject Headings (MeSH)

Transferase: one carbon transferases (EC 2.1)

2.1.1: Methyl-

N-	Histamine N-methyltransferase Phenylethanolamine N-methyltransferase Amine N-methyltransferase Phosphatidylethanolamine N-methyltransferase

O-	5-hydroxyindole-O-methyltransferase/Acetylserotonin O-methyltransferase Catechol-O-methyl transferase

Homocysteine	Betaine-homocysteine methyltransferase Homocysteine methyltransferase Methionine synthase

Other	Phosphatidyl ethanolamine methyltransferase DNMT3B Histone methyltransferase Thymidylate synthase DNA methyltransferase Thiopurine methyltransferase

2.1.2: Hydroxymethyl-,
Formyl- and Related

Hydroxymethyltransferase	Serine hydroxymethyltransferase 3-methyl-2-oxobutanoate hydroxymethyltransferase

Formyltransferase	Phosphoribosylglycinamide formyltransferase Inosine monophosphate synthase

Other	Glutamate formimidoyltransferase Aminomethyltransferase

2.1.3: Carboxy-
and Carbamoyl

Carboxy	methylmalonyl-CoA carboxytransferase

Carbamoyl	Aspartate carbamoyltransferase Ornithine carbamoyltransferase Oxamate carbamoyltransferase Putrescine carbamoyltransferase 3-hydroxymethylcephem carbamoyltransferase Lysine carbamoyltransferase N-acetylornithine carbamoyltransferase

2.1.4: Amidine

Arginine:glycine amidinotransferase

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases(list) EC2 Transferases(list) EC3 Hydrolases(list) EC4 Lyases(list) EC5 Isomerases(list) EC6 Ligases(list)

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