title: Alkylation of protein by methyl methanesulfonate and 1-methyl-1-nitrosourea in vitro.
abstract: Methylation of horse heart cytochrome c has been examined in vitro with [methyl-14C]methanesulfonate (MMS) and [1-methyl-14C]-1-nitrosourea (MNU) as alkylating agents. Analysis of protein hydrolyzates by an automatic amino acid analyzer indicates that, at pH 9.0 with MMS, epsilon-N-monomethyl-lysine is found to be the only major methylated basic amino acid. On the other hand, the identity of the predominant basic amino acid residue which is [methyl-14C]-labeled by MNU cannot be determined at present. Peptide mapping of chymotryptic digests of cytochrome c after reaction with MMS reveals a lack of specificity in methylation of a specific lysine residue in this hemoprotein.
mesh_terms: D000477:Alkylating Agents / Q000378:metabolism*; D000596:Amino Acids / Q000032:analysis; D002918:Chymotrypsin / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D011495:Histone-Lysine N-Methyltransferase / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008741:Methyl Methanesulfonate / Q000378:metabolism*; D008745:Methylation; D008770:Methylnitrosourea / Q000378:metabolism*; D009607:Nitrosourea Compounds / Q000378:metabolism*; D010455:Peptides / Q000032:analysis; D011496:Protein Methyltransferases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism
chemical_list: D000477:Alkylating Agents; D000596:Amino Acids; D003574:Cytochrome c Group; D009607:Nitrosourea Compounds; D010455:Peptides; D011506:Proteins; D008770:Methylnitrosourea; D008741:Methyl Methanesulfonate; D011496:Protein Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D002918:Chymotrypsin