[Antibiotic action on Bacillus polymyxa 153 enzymatic activity].

The study on the effect of some antibiotics on the activity of pyruvate dehydrogenase (PDG) and dehydrogenases of the tricarboxylic acid cycle (TAC) in the cell extracts of Bac. polymyxa 153 producing polymyxin B showed that the level of the reaction of the individual enzymes to the effect of various antibiotics was different. Specific sensitivity to polymyxins M and B was found in succinate dehydrogenase and that to polymyxin B in malate dehydrogenase. The activity of the first components of the pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase complexes was completely suppressed not only by polymyxins M and B but also by novobiocin, ristomycin and nistatin. The activity of NADP-dependent isocitrate dehydrogenase was not suppressed by either of the antibiotics tested.