70] Trypsin-plasmin inhibitors (Bdellins) from leeches

Abstract

Publisher Summary The occurrence of the thrombin-specific inhibitor hirudin in salivary glands of the leech Hirudo medicinalis is well known. Commercially available samples of hirudin contain, however, in addition to the thrombin-specific inhibitor, large amounts of trypsin-plasmin inhibitors and an appreciable amount of a chymotrypsin inhibitor. Bdellins occur in all parts of the body of the leech, but the highest concentration is found in the region of the outer sexual organs. This indicates perhaps a functional relationship to the trypsin or trypsinplasmin inhibitors occurring in seminal vesicles s or seminal plasma, which, like the bdellins, are strong inhibitors of the sperm acrosomal proteinase acrosin. In view of a possible therapeutic use of the bdellins, it is of interest to note that they are excreted into the urine after intravenous injection. This chapter details the assay methods used to estimate the inhibition of the enzymes. Known methods were used to estimate the inhibition of the enzymes employed: bovine trypsin and a-chymotrypsin, porcine and human plasmin, boar and human sperm acrosin, porcine pancreatic kallikrein, porcine and human plasma kallikrein and subtilisin Novo with the following substrates: Nα-benzoyl- DL -arginine ρ-nitroanilide (BAPA) (trypsin, porcine plasmin, acrosin), Nα-benzoyl- L -arginine ethyl ester (BAEE) (human plasmin, pancreatic and plasma kallikrein), Nα-succinyl-L-phenylalanine ρ-nitroanilide (SUPHEPA) (chymotrypsin), and azocasein (subtilisin). The chapter also discusses the purification procedure and the properties.