Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: KEGG:D03291 (CaCl2)
6,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Possible interactions between polymerized (F-) actin and insulin-storage granules from rat islets of Langerhans were examined in vitro by comparing the sedimentation of the granules in the presence of various actin concentrations. Actin in the concentration range 0.1--0.5 mg/ml produced a retardation in granule-sedimentation rates consistent with binding of the granules to the actin filaments. The interaction was increased by addition of ATP (2mM), but was decreased by CaCl2 (0.1 mM). Binding of granules to actin was unaffected by cyclic AMP or by preincubation of the granules with phospholipase C. Specificity of the interaction was confirmed by the use of depolymerized (G-) actin and of myosin to provide a solution of comparable viscosity; neither of these caused any alteration of granule sedimentation. Possible implications of this interaction of insulin-storage granules with actin for the mechanism of insulin secretion are briefly discussed.
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PMID:Interaction between insulin-storage granules and F-actin in vitro. 22 Sep 62

Plasma membrane and bile canalicular membrane fractions were prepared from rat liver using NaHCO3, NaHCO3--CaCl2, and K2HPO4-KH2PO4 buffers (all at pH 7.4). The amount (expressed as milligrams protein per gram liver) of plasma membrane fraction exceeded the amount of bile canalicular membrane fraction using each of these three media; the use of NaHCO3-CaCl2 afforded a substantially higher yield of both types of membranes. The two membrane fractions exhibited complex patterns of polypeptides (greater than 30) on sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis. Several reproducible differences in polypeptide patterns were observable between the two membrane fractions; in particular, components possibly corresponding to the heavy chain of myosin and to action were prominent in the bile canalicular membrane fraction. The effects of incubation in the above three buffers and in Tris--HCl (pH 7.4) on the polypeptide patterns of both types of membrane were studied. Many polypeptides were released from each type of membrane in all of these media. Differential effects on the polypeptide patterns of either type of membrane fraction were observed among the various buffers. In terms of minimizing loss of polypeptides, in general, NaHCO3--CacCl2 appeared to be the best buffer and Tris--HCl the worst buffer. The significance of these results for the preparation and storage of liver cell plasma membrane fractions is briefly discussed.
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PMID:Studies on the preparation of rat liver plasma membrane fractions and on their polypeptide patterns. 68 61

The relaxing effect and possible mechanism of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) on isolated rabbit artery were investigated. The addition of W-7 in concentrations ranging from 1 X 10(-6) to 3 X 10(-4) M caused a significant relaxation of isolated rabbit vascular strips contracted by KCl, prostaglandin F2alpha, norepinephrine, histamine, CaCl2, serotonin or angiotensin II. W-7 also caused a shift to the right of the dose-response curves for all agonists tested. Propranolol and atropine did not affect W-7 induced relaxation, suggesting that this drug does not act through beta adrenergic or cholinergic receptors. Superprecipitation of actomyosin from bovine aorta smooth muscle was inhibited by the addition of W-7 in a dose-dependent fashion. The concentration of W-7 which inhibited superprecipitation of bovine aorta smooth muscle actomyosin was in good agreement with the dose producing relaxation of isolated vascular strips. These facts suggest that W-7 produces relaxation of isolated vascular strips by inhibiting actin and myosin interaction.
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PMID:A novel vascular relaxing agent, N-(6--aminohexyl)-5-chloro-1-naphthalensulfonamide which affects vascular smooth muscle actomyosin. 70 53

The incorporation of 32Pi into ATP has been found to be catalyzed by myosin only when and if it interacts with actin. This exchange reaction is inhibited in natural but not in desensitized actomyosin after removing of trace Ca2+ with ethyleneglycol bis(2-aminoethyl)-N,N'-tetraacetic acid (EGTA). In desensitized as well as in synthetic actomyosin the exchange reaction can be fully inhibited by the addition of troponin I (0.5 mg troponin I/mg actomyosin results in a 50% inhibition) or after replacing the Mg activator by CaCl2. The exchange rate is about 1:500 of the ATPase rate in presence of 2 mM phosphate. These results suggest the existence of an 'energy-rich' actin -- myosin -- nucleoside-diphosphate intermediate during the cross-bridge cycle.
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PMID:(32P) phosphate incorporation into ATP during ATP hydrolysis and its dependence on the interaction of actin and myosin. 81 2

Samples from pre- and post-rigor cod mince, surimi (a concentrate of fish myofibrillar proteins obtained after washing and dewatering the fish mince) and water from the first wash in the surimi manufacture, processed with and without the addition of 7.5 mM CaCl2 and 15 mM MgCl2, were analyzed by two-dimensional electrophoresis. The results showed that the main myofibrillar proteins, including myosin, actin and tropomyosin, remained in the surimi. Several other proteins were selectively removed during the washing procedure. Some additional major spots were detected in the two-dimensional gels containing samples of the wash water and surimi processed with the addition of Ca2+ and Mg2+ salts. These spots were either absent or present in minor amounts in the samples of post-rigor cod mince, wash water and surimi processed without Ca2+ and Mg2+ salts and in all the pre-rigor samples. This induced us to suggest that the new additional spots may constitute fragments of proteins originated by increased proteolytic activity during the surimi manufacture upon the addition of the Ca2+ and Mg2+ salts. Two-dimensional electrophoresis has proved to be a valuable tool to quickly and easily assess the effect of different processing conditions on the protein content of the products.
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PMID:Two-dimensional electrophoretic analyses of cod (Gadus morhua, L.) whole muscle proteins, water-soluble fraction and surimi. Effect of the addition of CaCl2 and MgCl2 during the washing procedure. 156 21

Adsorption isotherms of BSA at the solid-water interfaces have been studied as a function of protein concentration, ionic strength of the medium, pH and temperature using silica, barium sulphate, carbon, alumina, chromium, ion-exchange resins and sephadex as solid interfaces. In most cases, isotherms for adsorption of BSA attained the state of adsorption saturation. In the presence of barium sulphate, carbon and alumina, two types in the isotherms are observed. Adsorption of BSA is affected by change in pH, ionic strength and temperature of the medium. In the presence of metallic chromium, adsorbed BSA molecules are either denatured or negatively adsorbed at the metallic interface. Due to the presence of pores in ion-exchange resins, adsorption of BSA is followed by preferential hydration on resin surfaces in some cases. Sometimes two steps of isotherms are also observed during adsorption of BSA on the solid resins in chloride form. Adsorption of BSA, beta-lactoglobulin, gelatin, myosin and lysozyme is negative on Sephadex surface due to the excess adsorption of water by Sephadex. The negative adsorption is significantly affected in the presence of CaCl2, KSCN, LiCl, Na2SO4, NaI, KCl and urea. The values of absolute amounts of water and protein, simultaneously adsorbed on the surface of different solids, have been evaluated in some cases on critical thermodynamic analysis. The standard free energies (delta G0) of excess positive and negative adsorption of the protein per square meter at the state of monolayer saturation have been calculated using proposed universal scale of thermodynamics. The free energy of adsorption with reference to this state is shown to be strictly comparable to each other. The magnitude of standard free energy of transfer (delta G0B) of one mole of protein or a protein mixture at any type of physiochemical condition and at any type of surface is observed to be 38.5 kJ/mole.
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PMID:Protein adsorption at solid-liquid interfaces: Part IV--Effects of different solid-liquid systems and various neutral salts. 175 29

The isolated working rabbit heart preparation was used to study whether the "contractile machinery" remains unchanged in globally stunned myocardium. The function of the heart has been measured in nonischemic and postischemic conditions. The effect of isoprenaline or calcium chloride administration in both conditions was also studied. Myocardial contractile function was significantly depressed after 20-min global ischemia and returned to normal after CaCl2 and supranormal values after isoprenaline administration. From hearts used in experiments myofibrils were prepared and their ATPase activity was determined. It was observed that myofibrils prepared from "stunned" myocardium showed about 50% increase in ATPase activity in the presence of CaCl2. Subjection of the heart to ischemia caused a decrease in calcium sensitivity of the myofibrillar ATPase. Myofibrils obtained from ischemic hearts but subjected to isoprenaline or CaCl2 administration exhibited increased calcium sensitivity over that of control heart. These effects were accompanied by changes in the extent of phosphorylation of troponin I (TNI) and myosin light chains. The modification of contractile apparatus in the postischemic period described in this paper may contribute to the overall mechanism of myocardial stunning.
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PMID:Contractile proteins in globally "stunned" rabbit myocardium. 183 10

The epithelial layer lining the proximal convoluted tubule of mammalian kidney contains a brush border of numerous microvilli. These microvilli appear in structure to be very similar to the microvilli on epithelial cells of the small intestine. Microvilli found in both the small intestine and the proximal convoluted tubules in kidney have a core bundle of actin filaments bundled by the accessory proteins villin and fimbrin. Along the length of intestinal microvilli, lateral links can be observed to connect the core bundle of actin filaments to the membrane. These cross-bridges are comprised of a 110-kDa calmodulin complex which belongs to a class of single-headed myosin molecules, collectively referred to as myosin-1. We now report that an analogous calmodulin-binding polypeptide of 105 kDa has been identified in rat kidney cortex. The 105-kDa polypeptide is preferentially found in purified kidney brush borders, can be extracted with ATP, and co-elutes with calmodulin on gel filtration and anion exchange chromatography. Fractions containing the 105-kDa polypeptide exhibit a modest ATPase activity in buffer containing CaCl2. The partially purified 105-kDa polypeptide will bind iodinated calmodulin and will sediment with F-actin in buffer containing ethylene glycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) or Ca2+. The addition of ATP partially reverses this association with F-actin. These results indicate that myosin-1, in addition to its presence in intestinal brush borders, is present in the brush border of kidney. We also provide preliminary evidence to indicate that the 105-kDa polypeptide is not restricted to tissues possessing a brush border.
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PMID:Identification of the microvillar 110-kDa calmodulin complex (myosin-1) in kidney. 183 82

Extent of adsorption (gamma pw) of bovine serum albumin, beta-lactoglobulin, gelatin and myosin at the alumina-water interface has been measured as function of protein concentration (Cp) at several temperatures, pH, and ionic strengths of the medium. gamma pw for proteins in most cases increases with increase of protein concentration but it attains maximum value gamma pw(m) when Cp is high. Values of maximum adsorption have been examined in terms of molecular orientation, molecular size and shape and unfolding of the packed proteins at the interface. In few cases, gamma pw increases with increase of Cp without reaching a real state of saturation as a result of aggregation of molecules or extensive unfolding of the protein at the interface. In the case of beta-lactoglobulin at pH 5.2 and ionic strength 0.05, gamma pw in high concentration region decreases to zero value when Cp increases. For myosin at 45 degrees C and pH 6.4, and also at 27 degrees and pH 7.8, the values of gamma pw are all negative and these negative values increase with increase of Cp. All these results have been explained in terms of significant competitions of water and protein for binding to the surface sites of the powdered alumina. Adsorption of myosin has also been found to be affected in the presence of NaCl, KCl, CaCl2, KI, Na2SO4, LiCl and urea. The relative affinities of the adsorption of various proteins for the surface of alumina at different physical conditions of the system have been compared in terms of maximum values of adsorption attained when gamma pw is varied with Cp. The affinities are shown to be compared more precisely in terms of the standard free energy decrease for the saturation of the surface by protein as a result of the change in its concentration from zero to unity in the mole fraction scale.
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PMID:Protein adsorption at solid-liquid interfaces: Part I--Affinities of proteins for alumina surface. 187 68

Sustained smooth muscle contraction has been proposed to be regulated by either 1) sustained increases in intracellular Ca2+ concentration [(Ca2+]i)-dependent myosin phosphorylation or 2) diacylglycerol-dependent protein kinase C activation. We measured diacylglycerol mass with the diacylglycerol kinase assay and myoplasmic [Ca2+] with aequorin in swine carotid medial smooth muscle. Sustained and significant increases in [Ca2+], myosin light chain phosphorylation, and isometric stress were observed with histamine or endothelin stimulation. Neither stimuli, however, induced significant increases in diacylglycerol mass. Relaxation of histamine-stimulated tissues was induced by removal of histamine or removal of extracellular CaCl2 in the continued presence of histamine. The rate of decline of both [Ca2+] and force was similar in both protocols, suggesting that removal of Ca2+ (without removing the stimulus) was equivalent to removal of the stimulus. These data suggest that [Ca2+]i is the primary regulator of sustained swine arterial smooth muscle contraction, whereas diacylglycerol has, at most, only a minor role.
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PMID:[Ca2+], not diacylglycerol, is the primary regulator of sustained swine arterial smooth muscle contraction. 219 Sep 21


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