Ovochymase 1 (OVCH1)

A chymotrypsin-like protease contained in the perivitelline space of unactivated Xenopus eggs is released during egg activation and appears to participate in vitelline envelope conversion.Ovochymase was isolated from the exudate of activated eggs using a soy bean trypsin inhibitor-agarose affinity column. The column eluant contained only two proteins, the 30-kDa ovochymase plus a 78-kDa chymotrypsin-like proteolytic activity. The 78-kDa protease was not usually observed in fresh egg exudate samples and thus was activated during the purification process and may represent the proposed precursor of the 30-kDa protease.This conserved amino acid sequence, plus active site specific inhibition and substrate specificity studies, places ovochymase in the serine protease I family of enzymes. A two-dimensional protease activity gel revealed that ovochymase is present as several isozymes with a wide range of pI's.