Biochemical and Biological Properties of Leukocyte Intracellular Inhibitors of Proteinases

Abstract

Leukocyte proteinases are postulated to be involved in variety of physiological and pathological events (7,9). It has also been proposed that proteinases are involved in the process of malignant invasion and that they could be responsible for the altered growth control in tumor cells (14). In this context the so-called neutral proteinases — histonases are of interest. It has been suggested that the histone hydrolyzing proteinases remove histones, which are known to act as gene repressors by binding to the DNA double helix, and thus may cause the derepression which is followed by DNA synthesis and cell division (6). It has already been found that leukocyte, as well as spleen elastases and chymotrypsinlike neutral proteinases have the ability to catalyze the hydrolysis of histones (11). Relevant to this ability of neutral proteinases, proteinase inhibitors are of particular interest and many studies have appeared dealing with the effect of synthetic and protein inhibitors on neutral proteinases.