人心脏丙酮酸和酮戊二酸脱氢酶复合体的动力学特性
Kinetic characterization of the pyruvate and oxoglutarate dehydrogenase complexes from human heart.
作者信息
Kiselevsky Y V, Ostrovtsova S A, Strumilo S A
机构信息
Institute of Biochemistry, Byelorussian S. S. R. Academy of Sciences, Grodno, U. S. S. R.
出版信息
Acta Biochim Pol. 1990;37(1):135-9.
The Michaelis constant values for the highly purified pyruvate dehydrogenase complex (PDC) from human heart are 25, 13 and 50 microM for pyruvate, CoA and NAD, respectively. Acetyl-CoA produces a competitive inhibition of PDC (Ki = 35 microM) with respect to CoA, whereas NADH produces the same type of inhibition with respect to NAD (Ki = 36 microM). The oxoglutarate dehydrogenase complex (OGDC) from human heart has active sites with two different affinities for 2-oxoglutarate ([S]0.5 of 30 and 120 microM). ADP (1 mM) decreases the [S]0.5 values by a half. The inhibition of OGDC (Ki = 81 microM) by succinyl-CoA is of a competitive type with respect to CoA (Km = 2.5 microM), whereas that of NADH (Ki = 25 microM) is of a mixed type with respect to NAD (Km = 170 microM).
来自人心脏的高度纯化的丙酮酸脱氢酶复合物（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25、13和50微摩尔。乙酰辅酶A对辅酶A产生竞争性抑制作用（抑制常数Ki = 35微摩尔），而还原型烟酰胺腺嘌呤二核苷酸（NADH）对NAD产生相同类型的抑制作用（Ki = 36微摩尔）。来自人心脏的氧代戊二酸脱氢酶复合物（OGDC）具有对2-氧代戊二酸有两种不同亲和力的活性位点（半最大反应浓度[S]0.5分别为30和120微摩尔）。1毫摩尔的二磷酸腺苷（ADP）可使[S]0.5值降低一半。琥珀酰辅酶A对OGDC的抑制作用（Ki = 81微摩尔）相对于辅酶A（米氏常数Km = 2.5微摩尔）属于竞争性类型，而NADH（Ki = 25微摩尔）对NAD的抑制作用（Km = 170微摩尔）属于混合型。
Zotero 插件