CPM INHIBITS THE ACTIVATION OF THE CALCIUM RELEASE CHANNEL OF SKELETAL MUSCLE SARCOPLASMIC RETICULUM INDUCED BY 1,4NQ
CPM抑制了由1,4NQ诱导的对骨肌肌质网 SR钙通道RyR1的激活效应

By using an alkalating agent 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin (CPM) which specifically reacts with hypperreactive thiols in calcium release channel protein RyR1, the biphasic effect of 1,4-naphthoquinone (1,4NQ) on RyR1 was investigated. It shows that CPM could partially block the activation phase of either concentration or time dependence ryanodine binding induced by 1,4NQ,but had no effect on the inhibition phase. The samples were treated with or without CPM in the presence of various concentrations of 1,4NQ. Results show that neither activation nor inhibition effects of 1,4NQ could be removed by re-spin wash in the absence of CPM; while in the presence of CPM, only the activation effect of 1,4NQ can be washed out, but not the inhibition effect. All the data suggest that the hypperractive thiols identified by CPM are involved in the activation effect of 1,4NQ on the channel protein. By blocking the thiols on the activation site of RyR1, CPM inactivates the channel gating.