Abstract:

In this study, crude extract rich in cystine proteinase inhibitors (CPIs) from silver carp eggs was prepared by
homogenization, acidification and ultrafiltration. After purification by an array of chromatography on Sephacryl S-100,
SP-Sepharose Fast Flow, Blue Sepharose 6 Fast Flow and ConA Sepharose 4B, two high-molecular-weight (HMW) CPIs, a-2
and a-1 with or without absorption on ConA, were obtained. They were purified by 102.62 and 274.28 folds, with recoveries
of 2.02% and 1.42% respectively. Through analysis by TSK G2000 SWXL gel filtration HPLC and identification by
SDS-PAGE and reverse zymography, both part of a-1 recovered by HPLC and a-2 showed a single band on electrophoresis
with molecular weight of 139 and 92 ku, respectively. Both of them could inhibit cysteine protease (papain and silver carp
cathepsin L) but not serine protease (trypsin and chymotrypsin). From the characteristics, inhibitory activity and glycoprotein
features, a-1 and a-2 may be the different forms of kininogens in silver carp eggs.

Key words: silver carp egg, cysteine protease inhibitors, kininogen, purification, identification