Studies on Kanamycin B. I Isolation of Kanamycin B and Its Chemical and Biological Properties

Abstract

Besides a major antibiotic, kanamycin, a kanamycin-producing strain has been described by several authors to produce two or three active substances which were obtained by ion-exchange resin process. First, Umezawa et al. ⁽¹⁾ observed existence of kanamycin A and two other substances in their experiment of fractional precipitation of kanamycin reineckates, and they made paperchromatographic studies of active substances in the culture filtrate. Kanamycin showed Rf 0.21–0.26 by a paperchromatography using water-saturated butanol containing 2.0% p-toluenesulfonic acid, other two Rf 0 and Rf 0.37. The substance of Rf 0 had low toxicity and showed similar antibacterial spectrum as kanamycin A. But production of this substance was not constant. The substance of Rf 0.37 was described to be less effective against Mycobacterium 607 than kanamycin A.

Cron et al.⁽²⁾, Schmitz⁽³⁾ et al⁽⁴⁾, Gourevitch et al.⁽⁵⁾ and Umezawa et al.⁽⁵⁾, studied the substance of Rf 0.37 and it was named kanamycin B. According to these authors, kanamycin B was a water-soluble basic substance giving 2-deoxystreptamine, 3-glucosamine and other unidentified substances and its molecular weight was described to be 1,170. It has stronger inhibitory activity against microorganisms except against mycobacteria than kanamycin A. However, the latter is 2–4 times more active against mycobacteria than the former.

Thereafter, Rothrock et al.⁽⁶⁾ reported successful separation of kanamycins A and B by Dowex 1-x² resin chromatography. In this experiment, they determined electroconductivity and bacteriostatic activity of each fraction, and observed another active substance which was named kanamycin C.

Kanamycin B having higher bacteriostatic activity against test organisms than A confused results obtained by the cylinder plate method. Moreover, since as personally informed by Umezawa, kanamycin B had several times stronger toxicity than A, its percentage in the commercial products should be strictly controlled. Thus, differential assay of B from A was an important subject of our studies. We isolated kanamycin B, studied its chemical and biological properties, and established an useful method of determining B. In this paper, isolation, and properties of B are presented and the differential assay of B will be in next paper.