膜透過性が支配する2,3の代謝生活について

概要

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In this review some examples of in vivo metabolic activity controlled by substrate permeation are dealt with. Substrate permeation can regulate the in vivo metabolic activity by two mechanisms : one is affecting the induction of the enzyme(s)by means of the absence of the inducer, and the other is by the absence of metabolite in the cytoplasm. These two mechanisms are considered to be operative at different substrate concentrations in the cytoplasm; in the case of Saccharomyces cerevisiae the former mechanism would be available at less than 10^<-5> to 10^<-6>M α-methylglucoside concentration in the cytoplasm, above that concentration the latter mechanism would be operative. In case of actively metabolizing microorganisms, for example in α-methylglucoside fermenting S. cerevisiae, the rate limitting step of the all over metabolism was shown to be the active transport of the sugar into the cytoplasm for folloqing reasons : (1) The pH-activity curves of the in vivo α-methylglucoside fermentation and that of the α-thioethyl-D-glucopyranoside (α-TEG, an anologue of α-methylglucoside) uptake, showed good agreement.(Fig. 3) (2) The km value of α-methylglucoside fermentation and the Ki value of α-methylglucoside against α-TEG uptake were the same within experimental error.(3) The fermentation rate of α-methylglucoside and the uptake rate of α-TEG showed good agreement.
社団法人日本生物工学会の論文
1964-02-15