Mechanism of Production of Troponin T Fragments during Postmortem Aging of Porcine Muscle

详细信息    查看全文

• 作者：Shin-ichi Kitamura ; Susumu Muroya ; Soichi Tanabe ; Tomoyuki Okumura ; Koichi Chikuni ; and Toshihide Nishimura
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：May 18, 2005
• 年：2005
• 卷：53
• 期：10
• 页码：4178 - 4181
• 全文大小：116K
• 年卷期：v.53,no.10(May 18, 2005)
• ISSN：1520-5118

文摘

Troponin T (TnT) is one of the myofibrillar proteins that is easily degraded during postmortem agingof pork. In this study, we determined the N-terminal amino acid sequences of TnT degradationfragments produced during postmortem aging and by m-calpain hydrolysis. The N-terminal aminoacid sequences of TnT fragments produced during postmortem aging were EVHEPEEKPRPKLTAP,EKPRPKLTAPKIPEG, and APKIPEGEKVDF. On the other hand, the N-terminal amino acid sequencesof TnT fragments produced by the action of m-calpain were APPPPAEV, EVHEPEEK, and APK.These sequences of degradation fragments could be mapped on fast type TnT isoform 2. The peptide bonds of His₃₇-Glu₃₈ and Thr₅₁-Ala₅₂ in fTnT2 were cleaved during postmortem aging as wellas by the calpain hydrolysis; therefore, calpain was concluded to have an important role in TnTdegradation during postmortem aging. It was also found that the sourness-suppressing peptideAPPPPAEVHEVHEEVH (Okumura et al. Biosci. Biotechnol. Biochem. 2004, 68, 1657-1662) derivedfrom TnT degradation could be produced by the action of calpains on Glu₂₁-Ala₂₂ and His₃₇-Glu₃₈sites.Keywords: Troponin T (TnT); postmortem aging; calpain; porcine; degradation; N-terminal amino acidsequence