1245
Analysis of Porcine Myosin Heavy Chain Isoforms by Liquid Chromatography and Mass Spectrometry

Monday, July 21, 2014
Exhibit Hall AB (Kansas City Convention Center)
Gap-Don Kim , Department of Food Science and Biotechnology, Kyungnam University, Changwon, South Korea
Eun-Young Jung , Division of Applied Life Science, Gyeongsang National University, Jinju, South Korea
Hyun-Woo Seo , Division of Applied Life Science, Gyeongsang National University, Jinju, South Korea
Jin-Yeon Jeong , Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, South Korea
Seon-Tea Joo , Department of Animal Science, Gyeongsang National University, Jinju, South Korea
Han-Sul Yang , Division of Applied Life Science, Gyeongsang National Universiy, Jinju, South Korea
Abstract Text: Myosin, a myofibrillar protein in the skeletal muscle, consists of two heavy chains (MHC) and four light chains. Nine MHC isoforms have been observed in muscles of mammalian species, and four MHC isoforms (I/slow, 2a, 2x, and 2b) were recognized in porcine skeletal muscle. MHC is a critical component that determines the metabolic and contractile properties of muscle fibers, which in turn related to meat quality. Therefore, analysis of MHC isoforms expression is important in animal muscles such as porcine and bovine skeletal muscle. However, MHC isoforms from porcine skeletal muscle is complicated due to the similarity in molecular weights among the MHC isoforms (i.e., 223.743, 223.924, 223947, and 224.010 kDa for MHC I/slow, 2a, 2x, and 2b, respectively). We analyzed the porcine MHC isoforms by LC-MS/MS system following SDS-PAGE electrophoresis. The longissimus dorsi muscle was taken from each of three commercial pigs (Landrace×Yorkshire×Duroc) for SDS-PAGE electrophoresis and LC-MS/MS analysis (Tempo nano-LC system, Applied Biosystems, CA, USA). A total of 525 unique peptides were identified and compared to each amino acid sequence of the porcine MHC isoforms. We selected four representative peptides that were identical to MHC I/slow, 2a, 2x, and 2b. The peptide identified as TLEDQLSEVKTKEEEHQR corresponds to residues 1253-1270 of MHC 2b, and differs from the other MHC isoforms (TLEDQLSELKSKEEEQQR, TLEDQLSELKTKEEEQQR, and TLEDQMNEHRSKAEETQR for MHC 2a, 2x, and I/slow). MHC 2x was confirmed by the peptide ELEGEVESEQKRNVETVK, which corresponds to residues 1925-1942. MHC I/slow and 2a were also confirmed by the unique peptides DIGTKGLNEE (residues 1926-1935) and TNAACAALDKK (residues 1539-1549), respectively. These types of unique peptides are useful for confirmation of MHC isoforms and could be used as MHC-specific markers for porcine skeletal muscle.

Keywords: Myosin heavy chain, Porcine skeletal muscle, LC-MS/MS

See more of: Meat Science & Muscle Biology Posters I
See more of: Meat Science and Muscle Biology
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