Incorporation of L-methionine-methyl-14C into gentamicins.

Gentamicin C complex, produced by Micromonospora purpurea1*2), is composed of three components, Cla, C2 and Q (Fig. 1). These components are methylaminoglycosides, which are distinct from other related antibiotics such as the kanamycins, neomycinsand paromomycins. As seen in Fig. 1, gentamicins Cla, C2, and Q possess one C-methyl and one N-methyl group, two C-methyl and one N-methyl groups and two C-methyl and two N-methyl groups, respectively. Presuming that L-methionine is the donor of methyl groups of gentamicins, it may be assumed that most of the radioactivity from L-methionine-methyl-14C would be incorporated into the Q component and least into the Cla component. Experimentally, incorporation of L-methionine-methyl14C into the gentamicins was found to be highest as compared to other radioactive presumed