When rabbit skeletal muscle myofibrils were treated with a solution containing 0.1 mM Ca2+ and 30 μg of leupeptin/ml, α-connectin, which forms very thin filaments in myofibrils, was split into β-connectin and a 1,200-kDa subfragment. A part of β-connectin located near the junction between β-connectin and the subfragment seems to have an affinity for calcium ions and to be susceptible to the binding of large amounts of calcium ions. The calcium- binding site on β-connectin is localized near the N2 line in the I band, and the subfragment Is localized adjacent to the Z disk. It is possible that connectin filaments change their elasticity during the contraction-relaxation cycle of skeletal muscle at the physiological concentration of calcium ions. Because postmortem skeletal muscles lose their elasticity and become plastic in association with the calcium-specific splitting of connectin filaments, the splitting is considered to be a factor in meat tenderization during postrigor ageing.
|ジャーナル||Journal of Biochemistry|
|出版ステータス||出版済み - 1 1 1992|
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