Isolation and purification of proteinase inhibitors from developing embryos of Hyalomma dromedarii

Abstract

The changes in the level of trypsin, chymotrypsin, subtilisin and papain inhibitors were examined during embryonic development of H. dromedarii. The high level of trypsin and chymotrypsin inhibitors in the oviposited eggs did not change during embryogenesis and was followed by a sharp drop after hatching. On the other hand, the papain inhibitor exhibited very low level throughout embryonic development and was followed by a significant increase in the newly hatched larvae. A purification scheme for trypsin and chymotrypsin inhibitors which involved chromatography on DEAE-cellulose, cellulose phosphate and Ultrogel AcA 54 was established. Using synthetic substrates six multiple forms of proteinase inhibitors with different molecular weights and properties were isolated. They were classified into three specific trypsin inhibitors F1a, F4a, and F4b, one specific chymotrypsin inhibitor F1b and to mixed trypsin-chymotrypsin inhibitors F2 and F3. Although treatment that may cause fragmentation of the native inhibitors were avoided during purification, multiple forms of trypsin and chymotrypsin inhibitor were isolated. The significancy of such multiplicity is not understood.