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Structural Changes in Titin and Nebulin Filaments Specific to Calcium Ions at 0.1 mM: Factors of Meat Tenderization During Postmortem Aging
Author(s) -
Tatsumi R.,
Takahashi K.
Publication year - 2003
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.2003.tb08237.x
Subject(s) - nebulin , titin , leupeptin , calpastatin , myofibril , chemistry , calcium , obscurin , biophysics , calpain , protease , biochemistry , sarcomere , microbiology and biotechnology , biology , myocyte , enzyme , organic chemistry
Postmortem structural changes in titin and nebulin filaments were investigated by incubating isolated myofibrils in a solution containing 0.1 mM calcium ions and various concentrations of a protease inhibitor. The inhibition curves showed 2 abnormal steps with increases in the concentration of leupeptin or calpastatin domain I. While the amounts of unchanged titin and nebulin were constant in the 1st step, the 2nd occurred at higher protease inhibitor concentrations. These facts indicated that excess amounts of leupeptin and calpastatin domain I caused deterioration in titin and nebulin properties, thus interfering with the binding of calcium ions. We concluded that the severance of titin and nebulin filaments in the 1st step were induced by calcium ions at 0.1 mM.