1988 Fiscal Year Final Research Report Summary
Functionality and Physicochemical Properties of Myofibrillar Proteins in Meat - Mechanism of Gelation -
| Project/Area Number |
61430025
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
畜産化学
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| Research Institution | Hokkaido University |
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Principal Investigator |
YASUI Tsutomu Faculty of Agriculture, Hokkaido University, 農学部, 教授 (20001373)
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| Co-Investigator(Kenkyū-buntansha) |
MORITA Jun-ichiro Agricultural Experiment Station, Faculty of Agriculture Hokkaido University, 農学部附属農場, 助手 (00001470)
SAMEJIMA Kunihiko Faculty of Dairy Science, College of Dairying, 酪農学部, 教授 (10048100)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Myosin / Myosin Isomers / Myosin Subfragments / Actomyosin / Heat-Denaturation / Heat-induced / Gelation |
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| Research Abstract |
The results obtained on the heat-induced gelation of myosin and actomyosin during 1986-1988 are as follows: 1. The denaturation of F-actin during heating under the same conditions as those for the heat-induced gelation of myosin proceeded through successive stages of (1) aggregation of actin filaments (30-40゜C), (2) loss of biological activities (45-50゜C) and (3) endothermic unfolding as revealed by DSC method (70-80゜C). 2. In the reconstituted acto-chemically modified myosin system, no substantial augmentation of the rigidity of the gel was observable. The results of 1. and 2. confer important clues to elucidate gelation mechanism of myosin monomers in the presence of actin. 3. Remarkable increase in the rigidity of thermogels from white skeletal and cardiac myosins was observed at pH 5.4, whereas no increase in the rigidity of heat-set gels of red skeletal myosin was recognized under the same condition. 4. Converting of myosin monomers to filaments through self-assocition procedure resulted in the similar change in rigidity. These results (3-4) strongly suggest an intimate relationship between filamentogenesis of the myosin used before heating and gel strength developed upon heating. 5. Studies on effects of myosin subfragments from respective myosin isomers on the thermogelation of the myosins implicated that different gelling hehaviors of the myosins were merely reflection of specific mode of filamentogenesis governed by the tail portion of each myosin isomer. 6. Lowering pH value of the myosin systen below 5.0 brought about pH-induced gelation. This is also reasonably explained by the filament-formability of myosin at low pH and simultaneous denaturation of cross-bridges which appeared as fringes of globular material surrounding filament backbone.
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