Purification and characterization of lizard fish pepsinogens and pepsins
【摘要】：正 Five pepsinogens were identified in lizard fish (Saurida wanieso) stomach and two of them (PG-Ⅰand PG-Ⅱ) were purified to homogeneity by column chromatographies on DEAE-Sephacel, Ultrogel AcA54, DEAE-Sepharose and Poly-L-Lysine Agarose. The molecular weights of the two purified PGs were about 41 kDa. Both pepsinogens were converted into pepsins within a few minutes under pH 2. 5. Corresponding pepsins were also purified by a chromatography on S-Sepharose and their molecular weights were 36 kDa as determined on SDS-PAGE. Optimum pHs of the pepsins were around 3. 5 and optimum temperatures were 45℃using hemoglobin as substrate. Both enzymes showed high sensitivity toward pepstatin A, a specific inhibitor of aspartic proteinases. The N-terminal amino acid sequences of PG-Ⅰand PG-Ⅱas determined to the 16th residue were exactly the same and showed high identity to pepsinogens of other animals.