title: Purification and identification of a protease inhibitor from glassfish (Liparis tanakai) eggs.
abstract: Two protease inhibitors of 67 and 18 kDa, respectively, were purified from glassfish, Liparis tanakai, eggs by affinity chromatography. The smaller protein was purified with a yield and purity of 0.25% and 49.69-fold, respectively, and was characterized for further study. The glassfish egg protease inhibitor exhibited stability between 50 and 65 degrees C in an alkaline environment (pH 8). It was shown to be a noncompetitive inhibitor against papain, with an inhibitor constant (Ki) of 4.44 nM. Potent glassfish protease inhibitor with N-Val-Gly Ser-Met-Thr-Gly-Gly-Phe-Thr-Asp-C amino acid residues was synthesized and its inhibitory activity was compared. Moreover, the 18-kDa protein inhibited cathepsin, a cysteine protease, more effectively than did egg white protease inhibitor, whereas the reverse was true for papain. Glassfish egg protease inhibitor is classified as a member of the family I cystatins.
authors.affiliation: Department of Fisheries, Faculty of Agriculture, Gadjah Mada University, Yogyakarta, Skip unit 1, Indonesia.
authors.forename: Ustadi
authors.initials: U
authors.lastname: Ustadi
authors.forename: K Y
authors.initials: KY
authors.lastname: Kim
authors.forename: S M
authors.initials: SM
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002403:Cathepsins / Q000037:antagonists & inhibitors; D002846:Chromatography, Affinity; D004355:Drug Stability; D005260:Female; D005399:Fishes; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D010063:Ovum / Q000737:chemistry*; D011480:Protease Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D011480:Protease Inhibitors; D002403:Cathepsins