ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
SUMMARY– Effects of postmortem storage of rabbit muscle at 25° on the properties of α-actinin and tropomyosin-troponin-containing fractions prepared from this muscle were studied. Postmortem storage did not affect the amount of α-actinin or tropomyosin-troponin that could be extracted from rabbit myofibrils by water washes or by a 3-day, pH 8.5, low-ionic strength extraction. Myosin B prepared from postmortem muscle underwent turbidity development much faster than myosin B prepared from muscle immediately after death. This increased rate of turbidity development was probably not due to postmortem changes in α-actinin, since the ability of α-actinin to accelerate the ATPase (for abbreviations used in this paper, see list under References) activity or the turbidity response of reconstituted actomyosin suspensions gradually decreased, rather than increased, during postmortem storage. However, even after 14 days postmortem at 25°α-actinin retained some activity in both the ATPase and turbidity tests. Moreover, the increased rate of turbidity development of postmortem myosin B was probably not due to degradation of the tropomyosin-troponin complex, since postmortem storage affected the activity of this complex only slightly and, even after 14 days post-mortem, the tropomyosin-troponin complex still conferred some Ca++-sensitivity on reconstituted actomyosin suspensions. Myosin B prepared from postmortem muscle did not contain more active α-actinin than myosin B prepared from muscle immediately after death, but the F-actin-tropomyosin-troponin interaction was gradually weakened during postmortem storage without any evident degradation of F-actin and the tropomyosin-troponin complex themselves. The weakened F-actin-tropomyosin-troponin interaction probably caused loss of Ca++-sensitivity in myosin B prepared from postmortem muscle. Results of this study indicate that postmortem changes in α-actinin and the tropomyosin-troponin complex per se are not the primary cause of postmortem modification in the actin-myosin interaction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1970.tb01976.x
