期刊
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY
卷 147, 期 4, 页码 682-689出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.cbpb.2007.04.008
关键词
pepsin; acidic proteinase; purification; isolation; fish; viscera; stomach
Two pepsins (A and B) were purified from the stomach of pectoral rattail (Coryphaenoides pectoralis) by acidification, ammonium sulfate precipitation, gel filtration chromatography and anion exchange chromatography to obtain a single band on native-PAGE and SDS-PAGE. The purities of pepsin A and B were increased to 7.1- and 13.0-fold with approximately 5.7% and 2.2% yield, respectively. Pepsin A and B had the apparent molecular weights of 35 and 31 kDa, respectively, when analyzed using SDS-PAGE and Sephacryl S-200 gel filtration. Pepsin A and B showed maximal activity at pH 3.0 and 3.5, respectively, and had the same optimal temperature at 45 degrees C using hemoglobin as a substrate. Both pepsin A and B were stable in the pH range of 2.0-6.0 but were unstable at the temperatures greater than 40 degrees C. Activity of both pepsins was inhibited by pepstatin A and was activated by divalent cations, indicating pepsin characteristics. Activities of both pepsins continuously decreased as NaCl concentration increased (0-30%). The enzymes had high affinity and activity toward hemoglobin with K-m and K-cat values of 98-152 mu M and 32-50 S-1, respectively. Purified pepsins generally showed the similar characteristics to other fish pepsins. (c) 2007 Published by Elsevier Inc.
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