Biogenesis of the L-N, -dimethylleucine residue of etamycin

Radioactive labeling experiments have shown that radioactivity from L -leucine-U-¹⁴C is incorporated into the L-N, β-dimethylleucine residue of the antibiotic etamycin, and that the N-methyl and β-methyl groups of this latter amino acid appear to be derived from L -methionine.