Kumar P M, Ward P H, Kassell B
Adv Exp Med Biol. 1977;95:211-22. doi: 10.1007/978-1-4757-0719-9_13.
The peptide comprising the first 16 amino acids of porcine pepsinogen, prepared from the activation mixture, has been modified by guanidination of its three lysine residues to form homoarginine residues. The modified peptide is a better pepsin inhibitor than is the native peptide; for 50% inhibition of the milk-clotting action of pepsin at pH 5.3, the molar ratio of peptide to pepsin required is 9 for the native inhibitor and only 2 for the guanidinated inhibitor. Stepwise removal by Edman degradation of the amino-terminal Leu-Fal-Homoarg residues from the guanidinated inhibitor decreased the activity slightly at the first step and markedly at the second and third steps. Thus, all of the amino-terminal sequence except the leucine residue is necessary for full activity.
从活化混合物中制备的包含猪胃蛋白酶原前16个氨基酸的肽，已通过对其三个赖氨酸残基进行胍基化修饰形成高精氨酸残基。修饰后的肽比天然肽是更好的胃蛋白酶抑制剂；在pH 5.3时，对于胃蛋白酶凝乳作用的50%抑制，天然抑制剂所需的肽与胃蛋白酶的摩尔比为9，而胍基化抑制剂仅为2。通过埃德曼降解从胍基化抑制剂中逐步去除氨基末端的Leu - Fal - 高精氨酸残基，在第一步时活性略有下降，在第二步和第三步时显著下降。因此，除亮氨酸残基外的所有氨基末端序列对于完全活性都是必需的。
