Poiarkov A A, Prokopenko V V, Poiarkova S A
Ukr Biokhim Zh (1999). 2011 Nov-Dec;83(6):35-45.
A substrate and inhibitor analysis of the thrombin interaction with synthetic peptide substrates and inhibitors of differing hydrophobicity and volume of the side amino acid residue, localized in the sub-centers thrombin S2 and S3 were carried out. The kinetic parameters of individual stages of the enzymatic reaction process (K(S), k2, k3) were estimated. It is shown that the efficiency of acylation and deacylation stages of the enzymatic reaction decreases with increasing hydrophobicity of the substituent in P2 as well as P3, at the same time the affinity of selected peptides toward enzyme is steadily increasing. With the aim to evaluate the hydrophobicity of compounds a LogP value was calculated and was made an attempt to compare them with the correspondent Ki values. Comparative kinetic analysis of Z-Arg-OMe and its uncharged analogue Z-Cit-OMe has shown the absence of uncharged analog hydrolysis, however, the mentioned citrulline derivate inhibits the hydrolysis of the charged analogue. These findings confirm the important role of hydrophobic moiety in the structure of thrombin inhibitors in preferential binding mode and inhibition of thrombin active side.
对凝血酶与位于凝血酶S2和S3亚中心、具有不同疏水性和侧链氨基酸残基体积的合成肽底物及抑制剂之间的相互作用进行了底物和抑制剂分析。估算了酶促反应过程各个阶段的动力学参数（K(S)、k2、k3）。结果表明，随着P2以及P3中取代基疏水性的增加，酶促反应的酰化和脱酰化阶段效率降低，同时所选肽对酶的亲和力稳步增加。为了评估化合物的疏水性，计算了LogP值，并尝试将其与相应的Ki值进行比较。对Z-Arg-OMe及其不带电荷的类似物Z-Cit-OMe的比较动力学分析表明，不存在不带电荷类似物的水解，然而，上述瓜氨酸衍生物抑制带电荷类似物的水解。这些发现证实了疏水部分在凝血酶抑制剂结构中以优先结合模式和抑制凝血酶活性位点方面的重要作用。
