Kay J, Afting E G, Aoyagi T, Dunn B M
Biochem J. 1982 Jun 1;203(3):795-7. doi: 10.1042/bj2030795.
Lactoyl-pepstatin (an acylated tetrapeptide) is much more readily soluble in aqueous media than the more common isovaleryl- and acetyl-pepstatins (acylated pentapeptides). However, the K1 value for inhibition of cathepsin D by lactoyl-pepstatin at pH 3.5 is approx. 10(-7) M, some two to three orders of magnitude weaker than has been obtained previously for isovaleryl- or acetyl-pepstatins. One of the peptides released during activation of pig pepsinogen is known to be an effective inhibitor of pig pepsin, but it does not alter the activity of the similar aspartic proteinase, pig cathepsin D.
乳酰胃蛋白酶抑制剂(一种酰化四肽)比更常见的异戊酰基和乙酰基胃蛋白酶抑制剂(酰化五肽)在水性介质中更易溶解。然而,在pH 3.5时,乳酰胃蛋白酶抑制剂抑制组织蛋白酶D的K1值约为10⁻⁷ M,比之前异戊酰基或乙酰基胃蛋白酶抑制剂所获得的值弱约两到三个数量级。已知在猪胃蛋白酶原激活过程中释放的一种肽是猪胃蛋白酶的有效抑制剂,但它不会改变类似的天冬氨酸蛋白酶——猪组织蛋白酶D的活性。