Biomaterial Database

Sodium-sensitive calcium binding to sarcolemma-enriched preparations from canine ventricle. 1984

M B Frankis, and G E Lindenmayer

Calcium binding to sarcolemma-enriched preparations from canine ventricle was evaluated. The preparation was exposed to calcium and 45Ca at physiological ionic strength, pH 7.4, for 15-18 hours at 5 degrees C. Bound calcium was separated from free by filtration and washing of the filter with solutions containing calcium and LaCl3. After equilibration at 5 degrees C, exposure to 37 degrees C caused an irreversible loss of binding. Monovalent cations (157 mM) reduced calcium binding: Na+ much greater than Li+ greater than Cs+ greater than K+ greater than Rb+ approximately equal to choline. In 1 microM calcium, divalent cations (3 mM) reduced binding: Sr++ greater than Ba++ greater than Mg++ approximately equal to Mn++. At 1-300 microM calcium, inhibition of the sodium-sensitive component of binding was characterized by I50's of 3.2-9.5 mM sodium. Comparison of binding by centrifugation versus filtration suggested that the sodium-sensitive component resided on constituents within the membrane vesicles. Calcium binding in 1 mM ethyleneglycol-bis-(beta-aminoethylether)N,N'-tetraacetic acid at pH 7.1 and 5 degrees C, revealed a single species of sodium-sensitive calcium-binding sites: Kd = 0.052 microM and Bmax = 6.73 nmol/mg. In 3 mM magnesium, the Kd was 0.205 microM and the Bmax was 9.03 nmol/mg. Nearly complete inhibition of binding was observed as sodium was raised from 1 to 10 mM. Thus, a substantial number of calcium-binding sites were detected at 5 degrees C in 3 mM magnesium at physiological ionic strength and pH 7.1. The affinity of these sites was in the range necessary to modulate intracellular free calcium. The sensitivity to sodium was at the lower end of the range estimated for intracellular sodium.

UI	MeSH Term	Description	Entries
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
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002498	Centrifugation	Process of using a rotating machine to generate centrifugal force to separate substances of different densities, remove moisture, or simulate gravitational effects. It employs a large motor-driven apparatus with a long arm, at the end of which human and animal subjects, biological specimens, or equipment can be revolved and rotated at various speeds to study gravitational effects. (From Websters, 10th ed; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D004285	Dogs	The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)	Canis familiaris,Dog
D004533	Egtazic Acid	A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.	EGTA,Ethylene Glycol Tetraacetic Acid,EGATA,Egtazic Acid Disodium Salt,Egtazic Acid Potassium Salt,Egtazic Acid Sodium Salt,Ethylene Glycol Bis(2-aminoethyl ether)tetraacetic Acid,Ethylenebis(oxyethylenenitrile)tetraacetic Acid,GEDTA,Glycoletherdiamine-N,N,N',N'-tetraacetic Acid,Magnesium-EGTA,Tetrasodium EGTA,Acid, Egtazic,EGTA, Tetrasodium,Magnesium EGTA
D005374	Filtration	A process of separating particulate matter from a fluid, such as air or a liquid, by passing the fluid carrier through a medium that will not pass the particulates. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Filtrations
D006352	Heart Ventricles	The lower right and left chambers of the heart. The right ventricle pumps venous BLOOD into the LUNGS and the left ventricle pumps oxygenated blood into the systemic arterial circulation.	Cardiac Ventricle,Cardiac Ventricles,Heart Ventricle,Left Ventricle,Right Ventricle,Left Ventricles,Right Ventricles,Ventricle, Cardiac,Ventricle, Heart,Ventricle, Left,Ventricle, Right,Ventricles, Cardiac,Ventricles, Heart,Ventricles, Left,Ventricles, Right
D000001	Calcimycin	An ionophorous, polyether antibiotic from Streptomyces chartreusensis. It binds and transports CALCIUM and other divalent cations across membranes and uncouples oxidative phosphorylation while inhibiting ATPase of rat liver mitochondria. The substance is used mostly as a biochemical tool to study the role of divalent cations in various biological systems.	4-Benzoxazolecarboxylic acid, 5-(methylamino)-2-((3,9,11-trimethyl-8-(1-methyl-2-oxo-2-(1H-pyrrol-2-yl)ethyl)-1,7-dioxaspiro(5.5)undec-2-yl)methyl)-, (6S-(6alpha(2S,3S),8beta(R*),9beta,11alpha))-,A-23187,A23187,Antibiotic A23187,A 23187,A23187, Antibiotic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining