Rigbi M, Katcoff D J
Int J Pept Protein Res. 1977;9(4):272-6. doi: 10.1111/j.1399-3011.1977.tb03491.x.
The C-terminal undecapeptide of ovine prolactin, H-Leu-Asn-Cys-Arg-Ile-Ile-Try-Asn-Asn-Asn-Cys-OH possesses several structural features common to protein proteinase inhibitors, yet has no inhibitor properties. The undecapeptide is completely hydrolysed by trypsin (Arg-Ile bond) and by chymotrypsin (Tyr-Asn bond), with a proteolytic coefficient of approximately 3,000 M-1 sec-1 and 240 M-1 sec-1 respectively. On the basis of these results, a consideration of entropy, and studies by other workers, we agree with the view of Nishino et al. that the best models for small synthetic peptides with inhibitor properties would be those naturally-occurring inhibitors whose reactive site is located within a small disulphide loop.
绵羊催乳素的C末端十一肽，H-亮氨酸-天冬酰胺-半胱氨酸-精氨酸-异亮氨酸-异亮氨酸-色氨酸-天冬酰胺-天冬酰胺-天冬酰胺-半胱氨酸-OH，具有一些蛋白酶抑制剂共有的结构特征，但却没有抑制特性。该十一肽能被胰蛋白酶（精氨酸-异亮氨酸键）和糜蛋白酶（酪氨酸-天冬酰胺键）完全水解，其蛋白水解系数分别约为3000 M⁻¹秒⁻¹和240 M⁻¹秒⁻¹。基于这些结果、对熵的考虑以及其他研究人员的研究，我们赞同西野等人的观点，即具有抑制特性的小合成肽的最佳模型是那些活性位点位于小的二硫键环内的天然抑制剂。
