绵羊肾中琥珀酰辅酶A-3-氧代酸辅酶A转移酶的初速度动力学
Initial-velocity kinetics of succinoyl-coenzyme A-3-oxo acid coenzyme A-transferase from sheep kidney.
作者信息
Sharp J A, Edwards M R
出版信息
Biochem J. 1983 Jul 1;213(1):179-85. doi: 10.1042/bj2130179.
The initial-velocity kinetics of sheep kidney CoA-transferase are consistent with a Ping Pong mechanism. A KAcAc-CoA of 2.7 X 10(-5) M, KSucc-CoA of 1.6 X 10(-4) M, KSucc of 5.6 X 10(-3) M and KAcAc of 6.7 X 10(-5) M were determined by using a direct assay system that monitors the concentration of magnesium acetoacetyl-CoA enolate. However, product-inhibition kinetics of sheep kidney CoA-transferase are inconsistent with a Ping Pong mechanism. The possible involvement of separate binding sites for succinate and acetoacetate are discussed.
绵羊肾辅酶A转移酶的初速度动力学符合乒乓机制。通过使用监测乙酰乙酰辅酶A烯醇镁浓度的直接检测系统，测定出乙酰乙酰辅酶A的米氏常数（KAcAc-CoA）为2.7×10⁻⁵ M，琥珀酰辅酶A的米氏常数（KSucc-CoA）为1.6×10⁻⁴ M，琥珀酸的米氏常数（KSucc）为5.6×10⁻³ M，乙酰乙酸的米氏常数（KAcAc）为6.7×10⁻⁵ M。然而，绵羊肾辅酶A转移酶的产物抑制动力学不符合乒乓机制。文中讨论了琥珀酸和乙酰乙酸可能存在单独结合位点的情况。
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