Isolation and characterization of ovochymase, a chymotrypsin-like protease released during Xenopus laevis egg activation.
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. This 30-kDa protease, which we have termed 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. The 30- and 78-kDa proteases were separated by gel filtration HPLC or by SDS-PAGE. The N-terminal amino acid sequence of SDS-PAGE-isolated ovochymase was determined to be VVGGQQAAPR. 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.
Lindsay
L L
LL
Section of Molecular and Cellular Biology, University of California, Davis 95616.
Hedrick
J L
JL
D000595:Amino Acid Sequence; D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D010450:Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D066298:In Vitro Techniques; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009865:Oocytes / Q000201:enzymology*; D017386:Sequence Homology, Amino Acid; D014817:Vitelline Membrane / Q000201:enzymology; D014982:Xenopus laevis
D007527:Isoenzymes; D010450:Endopeptidases; C092314:ovochymase