真鲷肌肉蛋白的分解及影响因素

Degradation Profiles of Muscular Protein of Sea Bream (Pagrosomus major) and Affecting Factors

研究了真鲷死亡后肌肉蛋白在不同条件下的分解情况,以聚丙烯酰胺凝胶电泳(SDS-PAGE)和免疫印迹法对结果做鉴定分析,结果表明,当温度为25℃时,肌肉蛋白的分解作用不明显,温度超过40℃时,肌肉蛋白尤其是肌球蛋白重链(MHC)的分解显著;盐浓度的增加有利于MHC的分解,表明盐溶性蛋白MHC中的蛋白酶酶切位点随盐浓度的提高而更多暴露,易受蛋白酶的攻击;钙离子浓度变化对分解作用影响不大;即使在70℃下,无论是肌浆蛋白还是肌原纤维蛋白其分解作用仍很明显,表明参与分解作用的蛋白酶有高度热稳定性且在肌浆和肌原纤维中均有存在.

Sea bream muscular protein degradation under different conditions was investigated. Protein degradation was checked by SDS-PAGE or Western blot. No obvious degradation was observed at 25℃. However, significant degradation, especially the protein of myosin heavy chain （MHC） was identified above 40℃. MHC autolysis was enhanced with the addition of NaCl, suggesting the increasing of NaCl concentration accelerated the exposure of protein cleavage sites to proteases. Change of calcium concentration did not affect the degradation. Both sarcoplasmic and myofibrillar protein degradation were significant even under 70℃, indicating that the proteases responsible for the decomposition were thermal stable and exist not only in the sarcoplasmic but also in myofibrillar fractions.