Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanism of Ca2+ overload production in ischaemia-reperfusion of the heart is unclear. The present study was designed to examine whether loss of second messenger (Ca2+ and cyclic AMP) control of sarcolemmal Ca2+ transport systems occurs during ischaemia. Ischaemic (1, 2 and 3 h duration) and non-ischaemic tissue samples were taken from the coronary-ligated porcine heart and a membrane fraction, enriched in sarcolemmal vesicles, was isolated. The membranes were phosphorylated using [gamma-32P] ATP in the presence of either cyclic AMP or Ca2+-calmodulin. The in vitro 32P incorporation into the electrophoretically separated phospholamban-like protein, became markedly reduced depending on the duration of ischaemia. The reduction could neither be attributed to factors as ischaemia-induced changes in membrane-bound kinase or phosphatase nor in situ phosphorylation of phospholamban. It is postulated that during ischaemia and reperfusion, a deficient control of the sarcolemmal Ca2+ pump by phospholamban-like protein may serve as a source of intracellular Ca2+ overload.
J Mol Cell Cardiol 1986 Feb
PMID:Reduced in vitro 32P incorporation into phospholamban-like protein of sarcolemma due to myocardial ischaemia in anaesthetized pigs. 300 66

Glycerol was demonstrated as an end product of anaerobic glucose metabolism in Trichomonas vaginalis and Tritrichomonas foetus, produced in addition to acetate, H2, CO2, and lactate or succinate. In T. vaginalis strain C-1, glycerol amounted to 16% of the fermentation products and was formed at an average rate of 38 nmol min-1 (mg protein)-1. Corresponding figures for T. foetus strain KV1 were 7% and 4.8 nmol min-1 (mg protein)-1. The amounts of glycerol detected compensated almost exactly for the deficits in fermentation products recognized earlier, thus complete redox balances can now be provided for both organisms. The metronidazole-resistant T. foetus strain KV1-1MR-100 excreted only negligible amounts of glycerol and carried out an ethanol-CO2 fermentation. Aerobiosis hardly affected glycerol formation in T. vaginalis strains C-1 and NYH 286, but almost completely abolished it in T. foetus strain KV1. An NADP-dependent glycerol 3-phosphate dehydrogenase and a Mg2+-dependent glycerol 3-phosphatase were detected in the cytosol of both species. The phosphatase is distinct from the particle-bound nonspecific acid phosphatase. Glycerol kinase activity was not detected in either organism. Enhanced pCO2 did not affect the ratio of fermentation products in T. vaginalis strain C-1, but significantly increased the amount of succinate, and decreased the amounts of acetate, H2, and CO2, formed by T. foetus.
Mol Biochem Parasitol 1986 Jul
PMID:Glycerol, a metabolic end product of Trichomonas vaginalis and Tritrichomonas foetus. 301 35

The distribution of the spontaneous and trypsin-stimulated phosphorylase phosphatase activities between glycogen particles and cytosol was examined in muscle extracts obtained from rats that had been fasted, made diabetic with streptozotocin or injected with adrenaline. In all conditions the particle-bound phosphatase activities decreased, glycogen was degraded and phosphorylase was released from the particles into the cytosol. However, in fasting and diabetes (but not after adrenaline) the combined glycogen particle + cytosolic phosphatase activities decreased, indicating that the activity lost from the particles was not simply shifted to the cytosol. Fasting and diabetes (but not adrenaline) also decreased the phosphatase-activating ability of the muscle extracts, which was, at least in part, attributable to the protein kinase FA. These data indicate the presence of at least two different mechanisms affecting the phosphatase system, one modified by fasting and diabetes, the other by adrenaline.
Mol Cell Endocrinol 1986 Sep
PMID:Effects of streptozotocin-diabetes, fasting and adrenaline on phosphorylase phosphatase activities of rat skeletal muscle. 301 88

Leishmania donovani promastigotes contain intense tartrate-resistant cell surface acid phosphatase (ACP1) which blocks superoxide anion production by activated human neutrophils [A.T. Remaley et al. (1984) J. Biol. Chem, 259, 11173-11175]. An extensively purified preparation of ACP1 dephosphorylates several phosphoproteins which are phosphorylated at serine residues; these include: pyruvate kinase (Km 1.6 microM; Vmax 71.4 U (mg protein)-1), phosphorylase kinase (Km 0.076 microM; Vmax 5.4 U (mg protein)-1) and histones (Km 4.86 microM; Vmax 2.2 U (mg protein)-1). However, the specific activity of the leishmanial phosphatase on these phosphoproteins is very low as compared to other phosphoprotein phosphatases. The phosphatase activity of ACP1 was also low on phosphohistone phosphorylated at tyrosine residues. Phosphatidylinositol-4,5-diphosphate (PIP2) and inositoltriphosphate (IP3) were also tested as ACP1 substrates. PIP2 was hydrolyzed rapidly by ACP1. The rate of hydrolysis of PIP2 was higher at pH 6.8 (Km 2.35 microM; Vmax 107 X 10(3) U (mg protein)-1) than at pH 5.5 (Km 4.16 microM; Vmax 71 X 10(3) U (mg protein)-1). 32P-labeled IP3 was also a substrate for ACP1; the hydrolysis products consisted of a mixture of inositoldiphosphate and inositolmonophosphate. ACP1 and ten other phosphatases were tested for their ability to dephosphorylate proteins and to inhibit O2- production by stimulated human neutrophils. There was no correlation between the protein phosphatase activity of the acid- and alkaline phosphatases and their ability to block neutrophil O2- production. The results indicate that ACP1 probably blocks the production of reduced oxygen intermediates by a mechanism that does not involve dephosphorylation of phosphoproteins; however, the possibility that the parasite's phosphatase affects phagocyte metabolism by degrading PIP2 or IP3 should be considered.
Mol Biochem Parasitol 1986 Aug
PMID:Hydrolysis of phosphoproteins and inositol phosphates by cell surface phosphatase of Leishmania donovani. 301 59

Site-specific restriction endonuclease BbrI has been found in bacteriophage resistant strain B. bronchioseptica 4994. The technique was elaborated for purification of BbrI to the stage free of nuclease and phosphatase contamination. The yield of purified enzyme is 6000-20 000 units per 10 g of biomass. BbrI recognises and cleaves the same DNA sequence as HindIII with the formation of four-nucleotide cohesive ends. The simplicity of cultivation, security for human, presence of the single restriction endonuclease and the high level of its production make B. bronchioseptica 4994 a promising producer of BbrI restriction endonuclease, isoshizomeric to HindIII, for use in experimental practice in industry.
Mol Gen Mikrobiol Virusol 1986 Apr
PMID:[Isolation of a restriction endonuclease with HindIII-specificity from Bordetella bronchiseptica]. 302 98

The N-terminal part sequences of pituitary growth hormone, N alpha-acetyl-hGH 7-13 and hGH 6-13, promoted conversion of glycogen synthase b to glycogen synthase a in skeletal muscle and adipose tissue when injected intravenously. The peptides also caused conversion of phosphorylase a to phosphorylase b in liver and adipose tissue, but not in muscle, where the peptides antagonised activation of phosphorylase. Synthase phosphatase activity in muscle and phosphorylase phosphatase activity in liver increased after injection of peptide, with time courses of change similar to those seen for muscle synthase and liver phosphorylase activities. Injection of peptide also decreased both the cyclic AMP dependent and independent synthase kinase activities in muscle. These results show that the insulin-like activities of these peptides on glycogen synthase and phosphorylase involve both increases in protein phosphatase activities and inhibition of protein kinase activities. These results are discussed in relation to the insulin-like activities of growth hormone.
Mol Cell Biochem 1987 Mar
PMID:Activation of phosphoprotein phosphatases by growth hormone sequences with insulin-like activity. 303 64

The hamster hereditary cardiomyopathy provides a unique model for the study of membrane abnormalities during chronic congestive heart failure. It is associated with intracellular calcium accumulation, mitochondrial calcification and cell necrosis. Previous studies have shown a decrease in Na,K-ATPase activity purified from ventricle sarcolemma. The present study demonstrates a decrease in K-dependent 3-O-methylfluorescein phosphatase (3-O-MFPase) activity from 1.93 to 1.30 mumol/g wet wt. or 33% in crude homogenates from the left ventricle of 7-months-old cardiomyopathic hamsters as compared to control animals. This represents an equivalent decrease in Na, K-ATPase activity. The values are several times higher than previously published for membrane fractions of myocardium from the hamster. Concomitantly, there was an increase in intracellular Na-concentration of the myocardium of 42% whereas the K-concentration was unchanged. The decrease in Na,K-pump concentration may be of importance for the increase in intracellular sodium and ensuing calcifying necrosis observed in the myocardium of cardiomyopathic hamsters. It is emphasized that quantification of the Na,K-ATPase or Na,K-pump should preferably be performed using crude homogenates.
J Mol Cell Cardiol 1987 Jun
PMID:Heart Na,K-ATPase activity in cardiomyopathic hamsters as estimated from K-dependent 3-O-MFPase activity in crude homogenates. 304 Oct 9

Insulin alone at concentrations of less than 1 to 5 uU/ml increased the enzyme activities of glycogen synthase, synthase phosphatase, phosphorylase, and phosphorylase phosphatase in hepatoma H4 cells in culture in the presence and absence of serum. Increase in total and active forms of glycogen synthase and phosphorylase were observed. Cycloheximide blocked the action of insulin on glycogen synthase, glycogen synthase phosphatase and phosphorylase phosphatase. The enzymes with the exception of glycogen synthase phosphatase were expressed with greater hormonal sensitivity in the absence as compared to the presence of serum in terms of hormone concentration required and or time of onset. These results demonstrate that these glycogen metabolizing enzymes are under long term control by insulin, with glycogen synthase being the most sensitive of the enzymes studied to the action of the hormone.
Mol Cell Biochem 1987 Jun
PMID:Long term regulation of glycogen metabolizing enzymes by insulin in H4 hepatoma cells. 304 Dec

Metabolic labeling and immunoprecipitation experiments demonstrated that soluble acid phosphatase (EC 3.1.3.2) was rapidly synthesized and released into culture medium by Leishmania donovani promastigotes. The kinetics of release indicated a constitutive secretory process (t 1/2 = 45 min). Moreover, acid phosphatase was the major secretory protein. The extracellular enzyme is composed of two heterodisperse bands of approximately 110 and 130 kDa in sodium dodecyl sulphate-polyacrylamide gels. It is synthesized as two intracellular precursors of 92.5 and 107 kDa which acquire the heterodisperse form characteristic of the mature extracellular enzyme during biosynthesis. Labeling in the presence of tunicamycin altered the electrophoretic mobility of the acid phosphatase, indicating the presence of several N-linked oligosaccharides on the mature enzyme. However, tunicamycin did not block secretion of the enzyme or its processing to the heterodisperse form. The biosynthetic effect of tunicamycin was mimicked by N-glycosidase F treatment of acid phosphatase immunoprecipitates. In contrast to tunicamycin, labeling in the presence of monensin inhibited processing of the phosphatase to its heterodisperse form. This indicates that Golgi processing, probably glycosylation, is responsible for the heterodispersity of the mature enzyme in sodium dodecyl sulphate-polyacrylamide gels. As with tunicamycin, monensin treatment did not prevent secretion of the acid phosphatase. These cumulative results demonstrate that release of this enzyme by L. donovani promastigotes occurs via a secretory pathway.
Mol Biochem Parasitol 1987 Dec
PMID:Biosynthesis and secretion of acid phosphatase by Leishmania donovani promastigotes. 332 6

We have proposed a model that incorporates a dephosphorylated "latch bridge" to explain the mechanics and energetics of smooth muscle. Cross-bridge phosphorylation is proposed as a prerequisite for cross-bridge attachment and rapid cycling. Features of the model are 1) myosin light chain kinase and phosphatase can act on both free and attached cross bridges, 2) dephosphorylation of an attached phosphorylated cross bridge produces a noncycling "latch bridge," and 3) latch bridges have a slow detachment rate. This model quantitatively predicts the latch state: stress maintenance with reduced phosphorylation, cross-bridge cycling rates, and ATP consumption. In this study, we adapted A. F. Huxley's formulation of crossbridge cycling (A. F. Huxley, Progr. Biophys. Mol. Biol. 7: 255-318, 1957) to the latch-bridge model to predict the relationship between isotonic shortening velocity and phosphorylation. The model successfully predicted the linear dependence of maximum shortening velocity at zero external load (V0) on phosphorylation, as well as the family of stress-velocity curves determined at different times during a contraction when phosphorylation values varied. The model implies that it is unnecessary to invoke an internal load or multiple regulatory mechanisms to explain regulation of V0 in smooth muscle.
 ...
PMID:Regulation of shortening velocity by cross-bridge phosphorylation in smooth muscle. 338 2


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