Comparison of antiproteolytic activities of alpha-1-proteinase inhibitors from the plasma of some mammalian species.

The study investigates how alpha-1-proteinase inhibitors from different mammalian species interact with certain enzymes, providing insights into the possible reasons behind lung emphysema in humans and horses.

Research Objectives and Methodology

• The study aimed to analyze the interaction of alpha-1-proteinase inhibitors (alpha 1-PI) isolated from various mammalian plasmas with three types of horse leucocyte proteinases and bovine pancreatic trypsin and chymotrypsin.
• Species included in the research were horse, ox, pig, rabbit, and man.
• Scientists measured the effective molar ratio of enzyme-to-inhibitor, inactivation rate constant, and inhibition constant.

Findings

• In horse, ox, pig and rabbit, researchers found two principal electrophoretic forms of alpha 1-PI.
• These forms all effectively inhibited trypsin, but usually only one of them promptly and stoichiometrically reacted with chymotrypsin and leucocyte elastases.

Implications

• The differences in the reaction of the two forms of alpha 1-PI with enzymes may be a factor in the occurrence of diseases linked to proteinase activity, such as lung emphysema.
• The research suggests that genetic variability and functional heterogeneity of multiple forms of alpha 1-PI, as well as the lack of other tissue inhibitors of proteinases, can play a role in lung emphysema in humans and horses.