Gibson J L, Tabita F R
J Bacteriol. 1979 Dec;140(3):1023-7. doi: 10.1128/jb.140.3.1023-1027.1979.
The activation properties of the form I and form II ribulose 1,5-bisphosphate carboxylases from Rhodopseudomonas sphaeroides were examined. Both enzymes have a requirement of Mg2+ for optimal activity. Mn2+, Ni2+, and Co2+ can also support activity of the form I enzyme, whereas only Mn2+ can substitute for Mg2+ with the form II enzyme. The effect of different preincubations on the carboxylase reaction was also examined. Both enzymes exhibited a lag when preincubated with other than Mg2+ and CO2 before assay, but the lag was much more pronounced and the rate of the reaction was slower with the form I enzyme under these conditions. Activation of the form I carboxylase By Mg2+ and CO2 occurred more rapidly than that of the form II enzyme. The results obtained with the two distinct forms of carboxylase from R. sphaeroides, as well as studies with the spinach and Rhodospirillum rubrum enzymes, thus indicate that the presence of the small subunit affects the rate of activation by Mg2+ and CO2 as well as the rate of reactivation of ribulose bisphosphate-inactivated enzyme.
对球形红假单胞菌的I型和II型1,5-二磷酸核酮糖羧化酶的激活特性进行了研究。两种酶都需要Mg2+以达到最佳活性。Mn2+、Ni2+和Co2+也能支持I型酶的活性，而对于II型酶，只有Mn2+可以替代Mg2+。还研究了不同预孵育对羧化酶反应的影响。在测定前用除Mg2+和CO2之外的其他物质预孵育时，两种酶都表现出延迟，但在这些条件下，I型酶的延迟更为明显，反应速率也较慢。Mg2+和CO2对I型羧化酶的激活比II型酶更快。从球形红假单胞菌获得的两种不同形式羧化酶的结果，以及对菠菜和深红红螺菌酶的研究，因此表明小亚基的存在会影响Mg2+和CO2的激活速率以及1,5-二磷酸核酮糖失活酶的再激活速率。
