Studies on the Biosynthesis of Kanamycins

Streptomyces kanamyceticus produces 14C-kanamycin and other labeled kanamycin-related compounds in the presence of 14C-glucose or 14C-glucosamine. One of the latter is paromamine. In order to find a condition to obtain high incorporation rate of radioactive precursors, the culture phase for the addition of labeled compounds was studied. The maximal incorporation rate was obtained by addition of 14C-glucosamine in the later phase of the culture and the specific activity of resultant kanamycin A was found to be much higher than in the case of the addition of 14C-glucose. In some experiments one third of radioactivity of the added 14C-glucosamine was taken into kanamycin, and the distribution was limited only in 6-amino-6-deoxy-D-glucose moiety of kanamycin A when 14C-glucosamine was added. In contrast, when 1JC-glucose was added, approximately equal distribution of radioactivity was observed in each of three moieties of kanamycin A molecule.