清酒酵母に於げる変芽糖の適應的醗酵性 : 工業微生物の適應及び變異に關する研究報告 No. 1)

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The present investigation was undertaken in order to correlate the rate or extent of growth in the absence of exogenous nitrogen-source during adaptive course with that of adaptive acquisition of maltozymase on the one hand, and to acquire more detailed information as to the stability of adaptive enzyme and reversible inactivation thereof by the removal of the substrate, on the other. The organism employed was Sacch. Sake which does not or can scarcely ferment maltose prior to adaptation.It was pointedly emphasized, in the first place, that yeast cells freshly harvested from appropriate cultures can, as a rule, proliferate to a measurable extent on addition of assimilable sugar in the absence of exogenous nitrogen-source, and that the term "resting" should not be applied to these cases.In all instances presented, adaptive maltozymase is induced in cells of Sacch.Sake only in response to growth which, in our N-free suspensions, is permitted at the expense chiefly of endogenous nitrogen-source (see Table 1〜2,page 437-8).In actively proliferating adaptatin without exogenous nitrogen-source, rate of increase in Ym (Ym is gain in cell weight in the adaptive suspension) runs parallel with maltozymase activity and in logarithmic phase, which occupies main part of the entire course of increase, relative rates of increase in both values are approximately coincident, indicating that these two processes limit or control each other (Fig. 1〜2,page 439). In the subsequent phase of negative acceleration, deficiency in endogenous nitrogen-source for growth is supposed to limit the rate. Therefore, suspension of fully adapted cells is found in resting state in rigorous sense. The course of decrease in maltozymase activity of fully adapted cells in substrate-free suspension is analyzable into two different courses, the one of which is relatively rapid inactivation reversible by means of substrate supply (inactivation of substrate type), and the other is slower one which is almost indifferent to whether the substrate is present or not (spontaneous inactivation). Kinetic study of the inactivation of the former type shows that the course is perfectly reversible and the reactivation is of simply monomolecular nature (see Fig. 5〜6,pape 441-2).Spontaneous inactivation seems also to be a reversible one approaching to an equilibrium point although reverse process was not realized, and the effect of temperature upon the rate was proved to be similar to that of thermal inactivation of ordinary hydrolytic enzymes. Some ideas with regard to the formation, inactivation and reactivation of adaptive maltozymase in cells of Sacch. Sake derived from the above relationships are summarized in the schemes A〜D, presented in the text (page 445).
社団法人日本生物工学会の論文
1951-11-15

清酒酵母に於げる変芽糖の適應的醗酵性 : 工業微生物の適應及び變異に關する研究報告 No. 1)

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