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Purification and characterization of a sarcoplasmic serine proteinase from threadfin bream Nemipterus virgatus muscle

Liu, Jin-Yang, Yoshida, Asami, Gao, Yi-Li, Shirota, Kazuya, Shiina, Yasuhiko, Noguchi, Erika, Kuwahara, Koichi, Osatomi, Kiyoshi
Food chemistry 2019 v.284 pp. 198-204
Nemipterus, agarose, ammonium sulfate, bream, gels, molecular weight, muscles, myosin heavy chains, pH, polyacrylamide gel electrophoresis, serine proteinases, substrate specificity, surimi, temperature
A sarcoplasmic serine proteinase (SSP) was purified from threadfin bream (Nemipterus virgatus) belly muscle by ammonium sulfate precipitation and a series of chromatographies including Q-Sepharose, Phenyl Sepharose and Superdex 200. The SSP was purified 1967 folds with a yield of 4.8%. The molecular weight of the SSP was estimated to be 43.5 kDa and 22.5 kDa on SDS-PAGE under non-reducing and reducing conditions, respectively. The N-terminal amino acid sequence of the two protein bands were determined as IVGGYEXQPYSQAHQVSLNSGY and corresponded. It is suggested that the SSP exists as a homodimer. Optimum pH and temperature were 9.5 and 50 °C, using Boc-Val-Pro-Arg-MCA as a substrate. Substrate specificity and effects of inhibitors indicated that the SSP was a trypsin-like serine proteinase. The SSP was responsible for hydrolyzing myosin heavy chain (MHC) and inducing modori phenomenon in the threadfin bream surimi gel. Thus, the SSP was considered as a modori-inducing proteinase.