Methylated-DNA—(protein)-cysteine S-methyltransferase (original) (raw)

In enzymology, a methylated-DNA-[protein]-cysteine S-methyltransferase (EC 2.1.1.63) is an enzyme that catalyzes the chemical reaction DNA (containing 6-O-methylguanine) + protein L-cysteine DNA (without 6-O-methylguanine) + protein S-methyl-L-cysteine Thus, the two substrates of this enzyme are DNA containing 6-O-methylguanine and protein L-cysteine, whereas its two products are DNA and protein S-methyl-L-cysteine. The S-methyl-L-cysteine residue irreversibly inactivates the protein, allowing only one transfer for each protein.