Biomaterial Database

Phosphorylation of cardiac regulatory proteins by cyclic AMP-dependent protein kinase. 1976

Y S Reddy

Cardiac myofibrils were purified from canine myocardium, and the regulatory proteins (troponin + tropomyosin) were extracted and shown to contain endogenous cyclic AMP-dependent protein kinase activity. Other cyclic nucleotide stimulated the protein kinase activity but only at higher concentrations. The enzyme was able to catalyze phosphorylation of conventional substrates such as histones and casein as well as a component of the regulatory protein fraction with a molecular weight of 28,000 daltons. Endogenous phosphorylation required the presence of Mg2+ and was inhibited by Ca2+. A protein kinase inhibitor obtained from skeletal muscle inhibited the cyclicAMP-dependent phosphorylation. Escherichia coli alkaline phosphatase dephosphorylated the endogenous substrates. The level of phosphorylation found is severalfold higher than we have previously reported. A protein kinase, with its close association with the regulatory proteins, seems to be well suited to transmitting the message from the cyclic AMP to the regulatory proteins, a phenomenon that may influence the cardiac contractility via the troponin phosphorylation. The inhibitory effect of troponin on actomyosin might be changed by its state of phosphorylation.

UI	MeSH Term	Description	Entries
D009124	Muscle Proteins	The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.	Muscle Protein,Protein, Muscle,Proteins, Muscle
D009206	Myocardium	The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.	Muscle, Cardiac,Muscle, Heart,Cardiac Muscle,Myocardia,Cardiac Muscles,Heart Muscle,Heart Muscles,Muscles, Cardiac,Muscles, Heart
D009210	Myofibrils	The long cylindrical contractile organelles of STRIATED MUSCLE cells composed of ACTIN FILAMENTS; MYOSIN filaments; and other proteins organized in arrays of repeating units called SARCOMERES .	Myofilaments,Myofibril,Myofilament
D009218	Myosins	A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.	Myosin ATPase,ATPase, Actin-Activated,ATPase, Actomyosin,ATPase, Myosin,Actin-Activated ATPase,Actomyosin ATPase,Actomyosin Adenosinetriphosphatase,Adenosine Triphosphatase, Myosin,Adenosinetriphosphatase, Actomyosin,Adenosinetriphosphatase, Myosin,Myosin,Myosin Adenosinetriphosphatase,ATPase, Actin Activated,Actin Activated ATPase,Myosin Adenosine Triphosphatase
D009712	Nucleotides, Cyclic		Cyclic Nucleotide,Cyclic Nucleotides,Nucleotide, Cyclic
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D010774	Phosvitin	An egg yolk phosphoglycoprotein which contains about 90% of the yolk protein phosphorus. It is synthesized in the liver of the hen and transferred to the developing oocyte, where it is bound to lipoproteins within the yolk granules.	Phosphovitellin
D011479	Protamines	A group of simple proteins that yield basic amino acids on hydrolysis and that occur combined with nucleic acid in the sperm of fish. Protamines contain very few kinds of amino acids. Protamine sulfate combines with heparin to form a stable inactive complex; it is used to neutralize the anticoagulant action of heparin in the treatment of heparin overdose. (From Merck Index, 11th ed; Martindale, The Extra Pharmacopoeia, 30th ed, p692)	Protamine,Protamine Sulfate,Protamine Chloride,Chloride, Protamine,Sulfate, Protamine
D011494	Protein Kinases	A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.	Protein Kinase,Kinase, Protein,Kinases, Protein
D011802	Quinidine	An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.	Adaquin,Apo-Quinidine,Chinidin,Quincardine,Quinidex,Quinidine Sulfate,Quinora,Apo Quinidine,Sulfate, Quinidine