Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Closed vesiculate preparations of pig myometrium sarcolemma (predominantly with inside-out orientation) are characterized by passive permeability for Ca2+. The kinetics of Ca2+ release from the vesicles is exponential. Using the grapho-analytical subtraction method, the kinetic parameters of this reaction were determined. Myometrium sarcolemma contains endogenous Ca2+-calmodulin-dependent protein kinase and phosphoprotein phosphatase which is inhibited by sodium o-vanadate. The Ca2+-calmodulin-dependent phosphorylation stimulates passive Ca2+ release from sarcolemmal vesicles. In the course of phosphorylation the capacity of the pool providing for rapid Ca2+ release increases by 61%, the initial rate of Ca2+ release showing a 28% increase. Trifluoroperazine, an inhibitor of Ca2+-calmodulin-dependent processes, eliminates the activating effect of phosphorylation on the rate of Ca2+ release from sarcolemmal vesicles.
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PMID:[Regulation by Ca2+-calmodulin-dependent phosphorylation of passive transport of Ca2+ in the myometrial sarcolemma]. 255 86

The effects of Ca2+, calmodulin, cAMP, the catalytic subunit of cAMP-dependent protein kinase (CSU) and some Ca2+ antagonists were studied in chemically (Triton X-100) skinned coronary smooth muscle. Calmodulin increased the Ca2+ responsiveness of the muscle fiber as indicated by the reduction in the threshold as well as the half-maximal activating Ca2+ concentration. Trifluoroperazine, a calmodulin antagonist, inhibited Ca2+-calmodulin-induced contraction. Both cAMP and CSU were effective inhibitors of contraction induced at an intermediate Ca2+ concentration. Fendiline, a Ca2+-antagonist, at 2 x 10(-4) M produced a significant inhibitory effect, which was reduced by increasing the Ca2+ concentration. From other Ca2+ antagonists tested, W-7, but not D600 and verapamil, produced some inhibitory effect. The data indicate that the response of skinned coronary smooth muscle to Ca2+, calmodulin and cAMP are similar to those obtained with other skinned smooth muscles. Furthermore, skinned fiber preparation can serve as a useful tool to investigate possible direct effects of drugs on the activating and regulatory systems in smooth muscle.
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PMID:Skinned coronary smooth muscle: calmodulin, calcium antagonists, and cAMP influence contractility. 631 55