pH值和酰基辅酶A链长度对心脏线粒体肉碱棕榈酰转移酶-I/肉碱辛酰转移酶转变为高亲和力、丙二酰辅酶A抑制状态的影响。
Effect of pH and acyl-CoA chain length on the conversion of heart mitochondrial CPT-I/CPTo to a high affinity, malonyl-CoA-inhibited state.
作者信息
Bieber L L, Wagner M
机构信息
Department of Biochemistry, Michigan State University, East Lansing 48824, USA.
出版信息
Biochim Biophys Acta. 1996 Aug 13;1290(3):261-6. doi: 10.1016/0304-4165(96)00028-1.
The effect of pH and acyl-CoA chain length on the conversion of the malonyl-CoA-sensitive carnitine palmitoyltransferase (CPT-I/CPTo) to a high-affinity, malonyl-CoA-inhibited state using a particle derived from rat heart mitochondria was determined. Preincubation with malonyl-CoA for one minute in the absence of acyl-CoA substrate lowers the IC50 for malonyl-CoA from 2 microM, 14 microM, and 15 microM at pH 7.4 to 15 nM, 14 nM, and 14 nM for decanyl-, lauryl-, and palmitoyl-CoA, respectively. Reducing the pH to 7.1 and 6.8 had little effect on the transition to the high affinity, malonyl-CoA-inhibited state. Preincubation of malonyl-CoA with the acyl-CoA, but not with L-carnitine, prevented the transition to the high affinity, malonyl-CoA-inhibited state.
利用大鼠心脏线粒体来源的微粒，测定了pH值和酰基辅酶A链长度对丙二酸单酰辅酶A敏感的肉碱棕榈酰转移酶（CPT-I/CPTo）转化为高亲和力、丙二酸单酰辅酶A抑制状态的影响。在不存在酰基辅酶A底物的情况下，与丙二酸单酰辅酶A预孵育一分钟，可使丙二酸单酰辅酶A的IC50分别从pH 7.4时的2 microM、14 microM和15 microM，降至癸酰辅酶A、月桂酰辅酶A和棕榈酰辅酶A的15 nM、14 nM和14 nM。将pH值降至7.1和6.8对向高亲和力、丙二酸单酰辅酶A抑制状态的转变影响不大。丙二酸单酰辅酶A与酰基辅酶A而非L-肉碱预孵育，可阻止向高亲和力、丙二酸单酰辅酶A抑制状态的转变。
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