No abstract

The relationship was studied between the energy metabolism of the actinomycete Streptomyces aureofaciens and the biosynthesis of chlorotetracycline by this organism. The energy charge values in a culture of low-production strain were almost identical with those of a production variant but the total sum of adenylates was about 10 times higher. In the stationary growth phase both strains evinced a drop in energy charge values followed by a rise to the original level. An increase in the concentration of inorganic phosphate in fermentation medium caused a suppression of antibiotic formation in the lowproduction strain and further rise in the total adenylate level. The expression of the energy charge in Streptomyces aureofaciens acquires a complex character owing to the participation, apart from the adenylate system, of high-molecular polyphosphates as energy donors and the probable lack of a regulating mechanism such as the adenylate kinase reaction.

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If a branched multistep editing mechanism is implemented by an enzyme with a single site for the specific substrates, there is no reason to believe that the number of testing steps is fixed and cannot be controlled by some external factors. The paper considers the mechanisms of single- or multistep editing done in response to various factors, particularly to the value of displacement from the reaction equilibrium. To avoid a complicated analysis of a fully specified case, which would be likely to obscure the general significant features, the operating modes of those mechanisms are estimated using the method of minimizing associated information gains. It turns out that sufficiently far from equilibrium the variable mechanisms can essentially operate just as well as the fixed multistep mechanisms.

No abstract