Marsh H C, Scott M E, Hiskey R G, Koehler K A
Biochem J. 1979 Dec 1;183(3):513-7. doi: 10.1042/bj1830513.
Kinetic parameters characterizing the slow structural isomerization observed via metal ion-dependent intrinsic fluorescence quenching of bovine prothrombin Fragment 1 have been determined. From forward and reverse rate constants, an equilibrium constant of approx. 0.25 is calculated. This result is consistent with the hypothesis that there exists, in the absence of metal ions, an equilibrium between two forms of bovine Fragment 1, one of which can interact rapidly with Ca2+ and subsequently with phospholipid. The other form of Fragment 1 cannot interact with Ca2+ in a manner that yields a phospholipid-binding form of the protein. Interconversion of these two forms of Fragment 1 occurs and may involve the isomerization of a proline residue.
已确定了通过金属离子依赖性牛凝血酶原片段1的固有荧光猝灭所观察到的缓慢结构异构化的动力学参数。根据正向和反向速率常数，计算出平衡常数约为0.25。该结果与以下假设一致：在没有金属离子的情况下，牛片段1的两种形式之间存在平衡，其中一种可以与Ca2+快速相互作用，随后与磷脂相互作用。片段1的另一种形式不能以产生蛋白质的磷脂结合形式的方式与Ca2+相互作用。这两种形式的片段1会发生相互转化，并且可能涉及脯氨酸残基的异构化。
