Czygier M, Strumiło S A
Department of Biochemistry, University of Warsaw, Białystok, Poland.
Acta Biochim Pol. 1994;41(4):453-7.
The purified aurochs (Bison bonasus, European bison) heart pyruvate dehydrogenase complex (PDC) has a set of subunits typical of mammalian PDC. PDC from aurochs heart contains firmly bound tiamine pyrophosphate in the amount providing over 50% of the maximal activity of the complex. The apparent value for activation energy of PDC is 60 kJ/mol. The Michaelis constant values for aurochs heart PDC are 22.4 +/- 1.0, 3.3 +/- 0.1 and 24.4 +/- 3.6 microM for pyruvate, CoA and NAD, accordingly. Acetyl-CoA is a competitive inhibitor with respect to CoA (Ki = 14.2 +/- 0.4 microM), whereas NADH gives the same inhibition with respect to NAD (Ki = 46.9 +/- 10.0 microM). The Km for CoA and NAD of the aurochs heart PDC are lower than that of domestic animals PDC.
纯化的原牛（欧洲野牛，Bison bonasus）心脏丙酮酸脱氢酶复合体（PDC）具有一组典型的哺乳动物PDC亚基。原牛心脏的PDC含有紧密结合的硫胺素焦磷酸，其含量提供了超过复合体最大活性50%的活性。PDC的活化能表观值为60 kJ/mol。原牛心脏PDC对丙酮酸、辅酶A和烟酰胺腺嘌呤二核苷酸（NAD）的米氏常数分别为22.4±1.0、3.3±0.1和24.4±3.6微摩尔。乙酰辅酶A是辅酶A的竞争性抑制剂（抑制常数Ki = 14.2±0.4微摩尔），而还原型烟酰胺腺嘌呤二核苷酸（NADH）对NAD具有相同的抑制作用（Ki = 46.9±10.0微摩尔）。原牛心脏PDC的辅酶A和NAD的米氏常数低于家畜PDC的米氏常数。
