タカアミラーゼAの変性に及ぼす圧力効果(<小特集>高圧力小特集)

概要

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The pressure effect on thermal inactivation, urea inactivation, Guanidine hydrochloride (Gu ・ HCl) inactivation of Taka-amylase A(TAA) and also its pressure inactivation habe been studied by measuring the rate of hydrolysis of p-nitrophenyl-α-maltoside (pNαM) catalyzed by TAA in the temperature range of 25〜75℃ and at the pressures up to 7 kbar. The apparent rate of hydrolysis decreased with time above a certain temperature, and concentration of denaturants of urea and Gu ・ HCl. The decrease is due to the decrease in TAA activity. The enthalpy change of the thermal inactivation was 580〜280 kJ ・mol^<-1>, which corresponds to the denaturation process of N_2 domain of TAA studied by thermal analysis. THe volume change of this process was 120〜79 cm^3 ・ mol^<-1>, while TAA was inactivated in the pressure range of 4〜7 kbar at 25 〜 45℃ and the corresponding volume change was -14〜-20 cm^3 ・ mol^<-1>. The pressure slightly depressed the urea inactivation and the volume change was 0〜7 cm^3 ・ mol^<-1>. On the other hand, the pressure accelerated the Gu ・ HCl inactivation at lower concentration of Gu ・ HCl (1.0 M) and the volume change was -10〜-20 cm^3 ・ mol^<-1>. At 2M Gu ・ HCl the volume change of inactivation was nearly zero.
社団法人日本材料学会の論文
1992-03-15