Liberation of Phospholipids from Z-Disks of Chicken Skeletal Muscle Myofibrils by 0.1 mM Calcium Ions : Weakening Mechanism for Z-Disks during Post-mortem Aging of Meat

概要

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Weakening of the Z-disks of skeletal muscle myofibrils contributes to the tenderization of meat during post-mortem aging. To elucidate the weakening mechanism, we compared Z-disks weakened by post-mortem aging of chicken breast muscle with those of myofibrils treated with a solution contaning 0.1 mM CaCl_2 and 1 μM calpastatin domain I. In both cases, the Z-disks were weakened with a corresponding liberation of their constituent phospholipids (PLs). The liberation of PLs specific to 0.1 mM calciumions was minimal at pH 6.5 and maximal at 35℃ together with the Z-disk weakening. Binding of calcium ions to PLs in the Z-disks was determined by ^<45>Ca-autoradiography. Acidic PLs were strongly radioactive and neutral PLs were appreciably radioactive. It is very probable that acidic PLs would bind electrostatically to α-actinin under physiological conditions, and that this interaction would be broken by the binding of calcium ions at 0.1 mM to PLs, resulting in the partial liberation of PLs from Z-disks. We conclude, therefore, that the liberation of PLs by the binding of 0.1 mM calcium ions was the main cause for Z-disk weakening during the post-mortem aging of chicken.
社団法人日本農芸化学会の論文
1998-05-23