Purification and characterization of a Cl- -activated aminopeptidase from bovine skeletal muscle.
To elucidate the mechanisms involved in the increase in free amino acids during postmortem storage of meat, a novel aminopeptidase was purified from bovine skeletal muscle by ammonium sulfate fractionation and successive chromatographies such as DEAE-cellulose, Sephacryl S-200, Hydroxyapatite, Phenyl-Sepharose, and Hi-Trap affinity column chromatography. The molecular mass of the enzyme was found to be 58 kDa on SDS-PAGE. This enzyme had optimum pH at around 7.5, and preferably hydrolyzed Ala-beta-naphthylamide (-NA) in amino acid-NAs. The activity was strongly inhibited by phenylmethansulfonyl fluoride (PMSF) and bestatin, suggesting that it is to be classified as a serine protease. Moreover, the activity was enhanced by chloride and nitrate ions, which is the most remarkable property of this enzyme. The enzyme appeared to be involved in the increase in free amino acids during postmortem storage of meat.
Migita
Koshiro
K
Graduate School of Biosphere Science, Hiroshima University, Japan.
Nishimura
Toshihide
T
D000409:Alanine / Q000031:analogs & derivatives / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D000626:Aminopeptidases / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D002417:Cattle; D002712:Chlorides / Q000737:chemistry*; D004789:Enzyme Activation; D004795:Enzyme Stability; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008461:Meat Products; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000201:enzymology*; D009566:Nitrates / Q000737:chemistry; D013379:Substrate Specificity
D000596:Amino Acids; D002712:Chlorides; D009566:Nitrates; C028104:alanine-beta-naphthylamide; D000626:Aminopeptidases; D000409:Alanine