Cytochrome c-specific protein methylase III from Neurospora crassa.
A protein methylase III responsible for specifically methylating the cytochrome c in Neurospora crassa was partially characterized by using unmethylated horse heart cytochrome c as a substrate. This enzyme utilizes S-adenosyl-L-methionine as the methyl donor. An analysis of the distribution of [14C]methyl groups in the peptides obtained by chymotrypsin digestion of the enzymically methylated cytochrome c showed that all of the radioactivity could be recovered within a single peak after chromatography. This indicates that the enzyme methylates a specific amino acid sequence within cytochrome c. On hydrolysis of the radioactive chymotryptic peptide, Me-14C-labelled epsilon -N-mono-methyl-lysine, epsilon-N-dimethyl-lysine and epsilon-N-trimethyl-lysine were identified. The enzyme can easily be extracted from the N. crassa mycelial pads and was purified approx. 30-fold.
D002918:Chymotrypsin / Q000494:pharmacology; D003574:Cytochrome c Group; D011495:Histone-Lysine N-Methyltransferase / Q000032:analysis* / Q000302:isolation & purification; D007700:Kinetics; D008239:Lysine / Q000494:pharmacology; D008745:Methylation; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000201:enzymology*; D011496:Protein Methyltransferases / Q000032:analysis*; D013347:Subcellular Fractions / Q000201:enzymology
D003574:Cytochrome c Group; D011496:Protein Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D002918:Chymotrypsin; D008239:Lysine