Strumilo S, Markiewicz J
Department of Biochemistry, University of Warsaw, Bialystok, Poland.
Biochem Mol Biol Int. 1995 Sep;37(1):101-6.
The purified 2-oxoglutarate dehydrogenase complex (OGDC) from the European bison heart was near saturated with endogenous bound thiamine pyrophosphate (TPP). Exogenous TPP added to the full OGDC reaction medium decreased S0.5 for 2-oxoglutarate approximately 2.6-fold without any notable change in the maximum reaction rate. The TPP effect was observed in the presence of 1 mM ADP which alone is a strong positive allosteric effector of OGDC. At an unsaturating 2-oxoglutarate concentration the A50 value for TPP was approximately 0.05 mM. The ADP-like action of exogenous TPP was also found in the 2-oxoglutarate dehydrogenase (E1) reaction, determined in the presence of 2,6-dichlorophenoloindophenol as an electron acceptor.
从欧洲野牛心脏中纯化得到的2-氧代戊二酸脱氢酶复合物（OGDC）几乎被内源性结合的硫胺素焦磷酸（TPP）饱和。添加到完整OGDC反应介质中的外源性TPP使2-氧代戊二酸的S0.5降低了约2.6倍，而最大反应速率没有任何显著变化。在存在1 mM ADP的情况下观察到了TPP效应，单独的ADP是OGDC的一种强正变构效应剂。在2-氧代戊二酸浓度不饱和时，TPP的A50值约为0.05 mM。在外源性TPP存在下，在以2,6-二氯酚靛酚作为电子受体测定的2-氧代戊二酸脱氢酶（E1）反应中也发现了类似ADP的作用。
