氮杂肽酯对半胱氨酸蛋白酶的抑制作用。

Cysteine protease inhibition by azapeptide esters.

作者信息

Magrath J, Abeles R H

机构信息

Brandeis University, Graduate Department of Biochemistry, Waltham, Massachusetts 02254.

出版信息

J Med Chem. 1992 Nov 13;35(23):4279-83. doi: 10.1021/jm00101a004.

DOI:10.1021/jm00101a004

PMID:1447732

Abstract

Papain, a prototype cysteine protease, was inhibited in a time-dependent manner by azapeptide esters designed to deliver an azaglycine group to the active-site thiol. For example, the rate of inhibition was 18 M-1s-1 for Ac-L-PheAglyOiBu (2) and > 11,000 M-1s-1 for Ac-L-PheAglyOPh (7). The rate of inhibition was slowed in the presence of substrate, and there was no reactivation of the inhibited enzyme after dialysis and incubation in the assay buffer. The inhibited enzyme was completely reactivated after the addition of valine methyl ester. The inhibited form of the enzyme is presumed to be acylated on the active-site thiol. An azaalanine-based peptide inhibited papain much more slowly. Azapeptide alkyl esters are unreactive with serine proteases; therefore, these inhibitors are selective for cysteine proteases.

摘要

木瓜蛋白酶是一种典型的半胱氨酸蛋白酶，它会被设计用于将氮杂甘氨酸基团传递至活性位点硫醇的氮杂肽酯以时间依赖性方式抑制。例如，对于Ac-L-PheAglyOiBu（2），抑制速率为18 M-1s-1，而对于Ac-L-PheAglyOPh（7），抑制速率> 11,000 M-1s-1。在底物存在的情况下，抑制速率会减慢，并且在测定缓冲液中透析和孵育后，被抑制的酶不会重新激活。加入缬氨酸甲酯后，被抑制的酶完全重新激活。推测酶的抑制形式是活性位点硫醇被酰化。基于氮杂丙氨酸的肽对木瓜蛋白酶的抑制作用要慢得多。氮杂肽烷基酯与丝氨酸蛋白酶无反应；因此，这些抑制剂对半胱氨酸蛋白酶具有选择性。