title: N-terminal amino acid sequences of troponin T fragments, including 30 kDa one, produced during postmortem aging of bovine longissimus muscle.
abstract: We have determined the amino (N)-terminal amino acid (AA) sequences of five troponin T (TnT) fragments produced during postmortem aging of bovine longissimus muscle. Western blot analysis showed that 32.1, 28.8, 27, and 25.8 kDa anti-fast-type TnT (fTnT)-positive fragments and a 31 kDa anti-slow-type TnT (sTnT)-positive fragment were present at 14 d postmortem. The N-terminal AA sequences of the 32.1, 28.8 (conventional 30 kDa), 27, and 25.8 kDa fragments were APPPPAEV, EVHEPEEK, EKPRPRLT, and APKIPEGE, respectively, and they were mapped to the N-terminal region of bovine fTnT isoforms. The N-terminal sequences of the 31 kDa fragment, EAPEEPEP, were mapped to the sTnT isoforms. These findings indicate that the two isoform types of fTnT predominantly expressed in the longissimus muscle are cleaved specifically at Glu(21)-Ala(22) and Glu(15)-Ala(16), His(37)-Glu(38) and His(31)-Glu(32), Glu(43)-Glu(44) and Glu(37)-Glu(38), and/or Thr(51)-Ala(52) and Thr(45)-Ala(46), respectively, and that a sTnT isoform is cleaved specifically at Glu(23)-Glu(24).
authors: Department of Animal Products, National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki 305-0901, Japan.
authors: Susumu
authors: S
authors: Muroya
authors: Shin-Ichi
authors: S
authors: Kitamura
authors: Soichi
authors: S
authors: Tanabe
authors: Toshihide
authors: T
authors: Nishimura
authors: Ikuyo
authors: I
authors: Nakajima
authors: Koichi
authors: K
authors: Chikuni