Methylation of canine cardiac myosin in culture.

N epsilon, N epsilon, N epsilon, trimethyllysine and an unidentified methylated amino acid which co-electrophoresed and co-chromatographed with the hydrolysis product of S-adenosyl-L-methionine, occur in fetal canine cardiac myosin and are isotopically labeled in vitro with S-adenosyl-L-(methyl 3H) methionine between the 10th and 12th day of culture.