酵母トリプトファン醗酵の酵素レベルでの研究

概要

論文の詳細を見る
The plots of τ (the specific rate of tryptophan production), the specific activities (units/g dry cell wt.) of TSase (B-protein and AB-complex) and InGPSase showed distinct peaks almost concurrently in cultures of Hansenula anomala. With an improved strain (I-22) empliyed in this work, the peak of μ (specific growth rate)-plot always appeared ca.10 hr in advance of the τ-peak, while with the original strain the two peaks appeared simultaneously as reported previously. The length of time interval between the two peaks (i.e.μ and τ) was discussed from the viewpoint of fermentation kinetics, and it was postulated (1) that the formation of a rate-limiting enzyme, which might probably be TSase, was closely associated with growth ; and (2) that the length of the above-mentioned time interval was a funciton of the rate of inactivation of the enzyme : the time interval would become shorter as the inactivation rate was higher. In other words, the peak of the specific activity of the rate-limiting enzyme would appear later as the stability of the enzyme was higher. The above postulation could partly be verified by experiments in which were tested the stabilities of TSase B and InGPSase in celles of varied culture ages : the changes of enzyme activities during incubation were measured in cells transferred to a nongrowing state. The specific rates of the enzyme formation (ε-values) were estimated by adding the specific rates of increase in enzyme activities to those of inactivation. It was shown that the ε-plots had peaks which appeared simultaneously with the μ-peak. Linear positive correlations of these enzymes with μ were shown in ε vs.μ plots. A tendency was observed that the stability of TSase B became higher as the culture was aged. Cells harvested from aged cultures contained a heat-stable, dializable factor active in protecting TSase B from inactivation. The factor fractionated by ion-exchange resin showed single spots on paper chromatograms. It exhibited a yellow color with a phenol-sulfuric acid reagent.
社団法人日本生物工学会の論文
1971-05-25

酵母トリプトファン醗酵の酵素レベルでの研究

スポンサーリンク

概要

著者

関連論文

スポンサーリンク