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)

1. A retrospective cross-sectional study was carried out on data derived from single 24 h urine collections from 246 male idiopathic calcium stone-formers. 2. The daily urine volume and pH and the exretions of calcium, oxalate, phosphate, creatinine and magnesium were related to the time of year when the urine was collected, and the saturation of urine with calcium oxalate and octocalcium phosphate calculated for each month. 3. There were significant seasonal variations in the urinary excretion of calcium and oxalate, each showing a maximum during the summer months and a minimum in the winter. There was no significant seasonal variation in urinary pH, volume, creatinine, phosphate or magnesium. 4. There was a significant increase in the saturation of urine with calcium oxalate and a trend towards higher saturation levels of octo-calcium phosphate in the summer. These changes were dependent only on the seasonal variation in urinary calcium and oxalate and not on urine volume. 5. A retrospective study of the seasonal incidence of stone episodes among these 246 stone-formers showed that the rate of stone passage per month was 50% higher in the summer than in the winter. There was no significant seasonal variation in the incidence of stones removed surgically.
Clin Sci Mol Med 1975 Dec
PMID:Seasonal variations in the composition of urine in relation to calcium stone-formation. 0 Nov 72

1. Angiotensin has previously been shown to inhibit distal renal tubular sodium reabsorption. As a consequence of this, or independently, it might influence the distal handling of other electrolytes. We have therefore examined the effects of angiotensin on the distal reabsorption or secretion of a spectrum of electrolytes. 2. Standard bilateral stop-flow studies were done on anaesthetized, adrenalectomized rabbits, in which the effects of intravenous infusions of either 0-02-0-05 mug min-1 kg-1 or 1 mug min-1 kg-1 of angiotensin were compared with control stop-flow results. 3. The lower dose of angiotensin inhibited distal sodium, chloride, water and magnesium reabsorption, inhibited distal hydrogen secretion and stimulated distal potassium secretion. The higher dose of angiotensin produced these changes and additionally inhibited distal calcium reabsorption. Most of the observed changes were dose-related. The low dose of angiotensin did not significantly raise blood pressure but the high dose was pressor. 4. Changes in the stop-flow patterns induced by the higher dose of angiotensin were compatible with, and may help to explain, the changes it produced in urinary excretion of sodium, chloride, potassium, magnesium and calcium in clearance studies before stop-flow. Suppression of hydrogen secretion caused by both doses of angiotensin in the stop-flow studies was also reflected by reductions in acid excretion produced by these infusion rates in additional experiments performed by clearance methods in acid-loaded, conscious rabbits. 5. The results support the view that angiotensin may have an important intrarenal role, at least in rabbits.
Clin Sci Mol Med 1976 Feb
PMID:Multiple changes in distal stop-flow electrolyte patterns and reduction of acid excretion induced in rabbits by angiotensin. 0 4

The effects of acid on fragmented sarcoplasmic reticulum from rabbit white skeletal muscle have been studied. Brief exposure of sarcoplasmic reticulum membranes to pH values in the range 5.5 to 6.0 at 37 degrees caused rapid inactivation of calcium accumulation measured at 25 degrees in the presence of oxalate (calcium uptake) while (Ca2+, Mg2+)-ATPase (EC 3.6.1.3) activity was enhanced by 75%. ATPase activity, measured at 37 degrees in the absence of oxalate and in the calcium steady state, was unaltered when calcium uptake was inactivated. Calcium efflux from sarcoplasmic reticulum vesicles, previously loaded passibely with 45CaCl2, was only slightly increased when calcium uptake was abolished. At still lower pH values, 5.0 to 5.5, (Ca2+, Mg2+)-ATPase was inactivated while Mg2+ ATPase was more acid-resistant. Acid inactivation of calcium uptake followed simple first order kinetics for at least 80% of the time course. The rate constant, k, increased from 0.043 min-1 to 1.63 min-1 between pH 6.50 and pH 5.35. At pH 4.65, Ea, the energy of activation, was 31 kcal mol-1 between 24 degrees and 43 degrees. Inactivation, once initiated, was irreversible. Aged suspensions of sarcoplasmic reticulum were more sensitive to acid inactivation. Ethylene glycol bis(beta-aminoethyl ether)N,N'-tetraacetic acid enhanced inactivation, and calcium specifically protected against inactivation with half-maximal effect at 1 to 2 mM. The sulfhydryl reagent, dithiothreitol (1 mM), caused significantly increased rates of inactivation. Calcium binding was studied by dual wavelength spectrophotometry and stopped flow analysis. Acid inactivation distinguished two ATP-induced binding sites, previously described (Entman, M. L., Snow, T. R., Freed, D., and Schwartz, A. (1973) J. Biol. Chem. 248, 7762-7772) as a superficial Mg2+-independent Site A which binds and releases calcium rapidly and a deeper Mg2+-dependent Site B which binds and releases calcium more slowly. Rates of binding to both sites were decreased by acid inactivation. Binding of calcium to Site A increased, however, from 4.6 to 6.4 nmol mg of protein-1 whereas that to Site B decreased from 17.0 to 6.9 nmol mg of protein-1. Passive binding of calcium to sites of medium affinity (K = 7 X 10(4) M-1) was unaffected by acid inactivation of calcium uptake. Temperature dependence of (Ca2+, Mg2+)-ATPase was unchanged in the range 9-34 degrees. Above 34 degrees, the higher activation energy process (Ealpha = 33.7 kcal mol-1) observed in control sarcoplasmic reticulum and thought to arise from a conformational change in the ATPase (Inesi, G., Millman, M., and Eletr, S. (1973) J. Mol. Biol. 81, 483-504) was diminished by acid inactivation (Ealpha = 8.2 kcal mol-1) in a manner suggesting that it is related to active calcium transport. The ATP in equilibrium 32Pi exchange reaction was diminished by acid, but 25% of the activity remained when calcium uptake was completely abolished...
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PMID:Proton inactivation of Ca2+ transport by sarcoplasmic reticulum. 1 42

1. The presynaptic mechanisms appear to be involved in the regulation of noradrenaline release during nerve stimulation. The first one. mediated by beta-adrenoceptors, operates at low frequencies of nerve stimulation, leading to an increase in transmitter release. The second one, mediated through alpha-adrenoceptors, is triggered when higher concentrations of the transmitter are reached in the synaptic cleft, leading to inhibition of transmitter release, probably through a restriction in the availability of calcium for the secretory process. 2. It is postulated that part of the anti-hypertensive effects of drugs like clonidine, alpha-methyldopa and beta-receptor-blocking agents may be related to their long-term effects on presynaptic adrenoceptors.
Clin Sci Mol Med Suppl 1976 Dec
PMID:The role of alpha- and beta-presynaptic receptors in the regulation of noradrenaline release elicited by nerve stimulation. 1 57

1. The acid, neutral and "intermediate" salts of calcium bilirubinate have been synthesized. 2. All are crystalline, and the intermediate salt which has 1 1/2 molecules of bilirubin per calcium atom probably has a crystal structure containing molecules of both acid and neutral salts. 3. The acid or intermediate salts have been found in 14 out of 70 gallstones analysed recently by X-ray diffraction.
Clin Sci Mol Med 1977 Jul
PMID:The crystalline salts of calcium bilirubinate in human gallstones. 1 1

Amylase from chicken pancreas was purified by an affinity method involving filtering a crude extract from pancreas through a Sepharose-wheat albumin column and eluting the retained enzyme with maltose. The purified amylase showed two active bands upon polyacrylamide electrophoresis in an alkaline buffer system and only one band in an acidic buffer system. The enzyme is a Ca2+-glycoprotein which behaves as a typical alpha-amylase. It consists of a single polypeptide chain with molecular weight 53,000 and contains 5.3 moles of reducing sugars per mole of protein. Optimal conditions of pH and temperature for the enzymic activity are 7.5 and 37 degrees C. The enzyme is irreversibly inactivated by removal of Ca2+ by exhaustive dialysis and is activated by the presence in the assay mixture of Cl-; other halides are less effective than Cl- in activating the enzyme.
Mol Cell Biochem 1977 Aug 19
PMID:Purification and properties of alpha-amylase from chicken (Gallus gallus L.) pancreas. 2 May 68

A calcium activated photoprotein, termed mnemiopsin, which emits bioluminescence upon the addition of calcium ion, has been isolated from the Ctenophore, Memiopsis leidyi, and purified by hollow fiber techniques. The system is similar to aequorin, from the jellyfish Aequorea, except that mnemiopsin can be light-inactivated. Separation of mnemiopsin from the dilute and large volume animal homogenate proved difficult with conventional biochemical techniques. A continuous flow process utilizing large surface area hollow fibers for filtration, concentration, and dialysis was developed which may also be applicable to the purification of other proteins. The resulting mnemiopsin concentrate, after further purification, was judged to be about 90% pure by its gel electrophoretic profile. Estimates by molecular sieve chromatography and SDS gel electrophoresis gave a molecular weight of about 23,000 daltons. A calcium specificity for triggering light emission was studied by comparison of triggering with a variety of cations and anions and by investigating the effects of calcium ionophores and antagonists. The activity of mnemiospin was characterized with respect to pH, temperature and ionic strength. The stability of mnemiopsin activity after exposure to proteases, denaturants, protein group specific reagents, detergents, elevated temperatures and light was determined. Some years ago our laboratory reported that the bioluminescence reaction in the ctenophores which had long eluded definition involved a calcium activated photoprotein similar in many respects to that found in other coelenterates, notably Aequorea. We found, moreover, that the systems differed in that the bioluminescent activity of the isolated protein was lost following exposure to light. The purification and characterization of this biochemical system was undertaken both in our laboratory and by Ward and Seliger. These latter reports provide a detailed and firm foundation for the understanding of the components and mechanisms involved. While many of our results are in agreement with theirs, our approaches, inquiries, and results differed in several significant ways, the description of which forms the basis for this report. In particular, we took a different approach in the purification of the Mnemiopsis photoprotein which in itself is rather a formidable task. The technique was successful and may point the way to other applications where large volume dilute solutions prove cumbersome. Secondly, our study of the effects of salts, proteases, detergents, and other agents indicate that the protein, though sensitive to calcium and visible light inactivation, is relatively resistant to some agents which commonly inactivate proteins.
Mol Cell Biochem 1978 Apr 11
PMID:The properties of mnemiopsin, a bioluminescent and light sensitive protein purified by hollow fiber techniques. 2 20

The effect of variations in pH and Ca2+ on angiotensin II (A-II)-induced steroidogenesis was tested on isolated adrenal glomerulosa cell suspensions. The results show that a reduction in pH from 7.4 to 6.5 produces both a shift to the left of the A-II dose-response curve as well as an increase in maximum steroid production. In contrast, removal of Ca2+ from the incubation medium virtually abolished steroidogenesis to A-II (5 X 10(-9)M(, KCl(10mM) and ACTH (250 microU/ml). The Ca2+ antagonist D-600, however, was less effective than simple removal of Ca2+ as 10(-4) M was required to block the steroidogenic response to these same agonists. The results indicate that the response characteristics of this system to A-II resemble most closely those seen with isolated arterial smooth muscle - especially rabbit aortic strips.
Mol Cell Endocrinol 1979 Feb
PMID:Angiotensin-induced steroidogenesis in rabbit adrenal: effects of pH and calcium. 3 13

Parathyroid follicle formation was studied in Mongolian gerbils subjected to different concentrations of calcium in vivo and in vitro, using light and electron microscopic methods, including the potassium pyroantimonate technique and x-ray microanalysis for identification of cations. Follicles were frequent at high calcium concentration, but sparse at intermediate and low levels of calcium. Two main types of follicle were differentiated: "degenerative follicles" containing cellular debris and lined by smooth-surfaced epithelium which occasionally showed degenerative changes; and "secretory follicles" characterized by amorphous and granular contents, and an epithelium possessing microvilli and cytoplasmic projections. Amorphous masses were also seen in dilated intercellular spaces and in dilated cisterns of rough endoplasmic reticulum in the follicle epithelium. Calcium-containing precipitates were found in degenerating chief cells, and between degenerating cells and follicles. Parathyroid follicles are believed to be formed by degeneration of suppressed chief cells (degenerative follicles), and by secretion of hormonal and/or other substances into dilated intercellular spaces which progressively increase in size to form follicular cavities (secretory follicles), thereby possibly reducing the level of metabolically active parathyroid hormone. Functional suppression is believed to underlie the development of parathyroid follicles.
Virchows Arch B Cell Pathol Incl Mol Pathol 1979 May 31
PMID:Experimental study of follicle formation in suppressed parathyroid glands of Mongolian gerbils. 3 63

cAMP independent glycogen synthase kinase and phosvitin kinase activity was purified from the 180 000 x g supernatant of human polymorphonuclear leukocytes by ammonium sulphate precipitation and phosphocellulose chromatography. The cAMP independent glycogen synthase kinase eluted from the phosphocellulose at 0.54 M NaCl (peak A) separate from the major phosvitin kinase eluting at 0.68 M NaCl (peak B). The kinase activity of both peaks tended to form aggregates, but in the presence of 0.6 M NaCl, the peak B enzyme had Mr 250 000, 7.2S and the peak A enzyme Mr 38 000, 3.8S. The ratio between synthase kinase and phosvitin kinase activity in peak A was 1:3.2 and in peak B 1:31.4. In addition the kinase activities differed with respect to sensitivity to temperature, ionic strength and CaCl2. It is suggested that the peak A enzyme represents the cAMP independent glycogen synthase kinase of leukocytes, whereas the peak B enzyme is a phosvitin kinase, which is insignificantly contaminated with some synthase kinase (peak A) and contains a separate, second synthase kinase. Synthase kinase had Kmapp 4.2 microM for muscle glycogen synthease I and Kmapp 45 microM for ATP. GTP was a poor substrate. The activity was not influenced by cyclic nucleotides, Ca2+, or glucose-6-P. Synthase I from muscle and leukocytes was phosphorylated to a ratio of independence of less than 0.05.
Mol Cell Biochem 1979 Jul 15
PMID:Purification and properties of cAMP independent glycogen synthase kinase and phosvitin kinase from human leukocytes. 4 Jan 8


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