Postmortem muscle protein degradation during ice-storage of Arctic (Pandalus borealis) and tropical (Penaeus japonicus and Penaeus monodon) shrimps: a comparative electrophoretic and immunological study

Water-, low-salt- and high-salt-soluble protein fractions from the abdomina l muscles of Pandalus borealis, Penaeus japonicus and Penaeus monodon extra cted immediately after death and after 5, 16, 24, 48, 72, 96 and 120 h (P b orealis) or 16, 22, 43, 71 and 92 h (Penaeus spp) of ice-storage were analy sed by one- and two-dimensional electrophoresis and immunological technique s. The most evident effect in P borealis was the decrease in the relative a mount of myosin heavy chain (MHC) and a concomitant increase in the number and intensity of bands of molecular size about 100kDa crossreacting with an ti-MHC antiserum. NMC degradation of P borealis was confirmed by sodium dod ecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of partially is olated native myosin. Other prominent features were the disappearance of ba nds of about 67 and 50kDa after 24h and the appearance of a band of slightl y less than 50kDa after 5 h of ice-storage. These last bands showed the pot ential to be used as freshness markers. One spot tentatively identified as desmin did not suffer significant changes in any of the three species. Two bands (about 100 and 96kDa) gave a positive reaction with the a-actinin ant ibody in the zero-time extract of P borealis, but after 24h only one faint 96kDa band was detected. In contrast, the extracts of P japonicus and P mon odon did not suffer significant alterations during the examined period, and even after 92h of ice-storage only the 100kDa anti-a-actinin cross-reactin g band was clearly visible in the high-salt extract of P japonicus. (C) 200 1 Society of Chemical Industry.