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. In a series of patients with sickle-cell anaemia, serum phosphate and magnesium concentrations were elevated. Serum calcium concentrations were normal. Urinary excretion of calcium was decreased. 2. The maximum tubular reabsorption of phosphate per litre of glomerular filtrate (TmP/GFR) was significantly increased in these patients. 3. The increase in phosphate reabsorption explains the elevated serum phosphate observed in these patients.
Clin Sci Mol Med 1978 Nov
PMID:The tubular reabsorption of phosphate in sickle-cell nephropathy. 71 96

The effect of thyroidectomy and replacement therapy on intracellular calcium was studied in isolated rat liver cells. The cells were first loaded with 45Ca and the efflux of isotope followed for 4 h. The cells maintained their viability during this period as judged from staining with trypan blue and rate of respiration. Two different time constants could be resolved by the peeling method. The experiments showed that thyroidectomy markedly reduced the pool of calcium with the slowest turnover while the other pool remained unchanged. Administration of triiodothyronine (T3) to the thyroidectomized animals 48 h before the experiment normalized the rate of respiration but did not restore the slow turnover pool of calcium.
Mol Cell Endocrinol 1978 Oct
PMID:Effect of thyroidectomy on intracellular amount and distribution of exchangeable Ca2+ in isolated rat liver cells. 72 Jul 46

Studies on the circular dichroic spectrum of cobalt-substituted concanavalin A have been continued in particular with respect to calcium- and saccharide-induced spectral pertubations reported previously (Kalb, A.J. and Pecht, I. (1973) Biochim. Biophys. Acta 303, 264-268; Richardson, C.E. and Behnke, W.D. (1976) J. Mol. Biol. 102, 441-451). We find that the addition of calcium or cadmium to (CO2+)-concanavalin A induces slow time-dependent alterations in the extrinsic cotton effects. Moreover, one equivalent of calcium is sufficient to cause maximal changes in the cobalt spectrum provided sufficient time is allowed for the effect to be observed. The addition of mono, di-and trisaccharides, specific for concanavalin A, have no resolvable effect upon the cobalt spectrum of concanavalin A (Richardson, C.E. and Behnke, W.D. (1976) J. Mol. Biol. 102, 441-451). The data presented here suggest that these time-dependent processes are conformationally mediated and occur subsequent to S2 occupancy. Evidence is presented that a particular calcium-cobalt-concanavalin A conformer exists which is responsible for the generation of activity in a light-scattering assay system.
 ...
PMID:Cobalt-concanavalin A. An index of inactive and active conformational states. 72 53

The effect of modification of photoreceptor membranes of the bovine retina on the termodynamical parameters that characterize heat denaturation of rodopsin was studied. The highest increase of the rate constant and the corresponding maximal drop of the free energy change of heat denaturation of the pigment were obtained by using 7 M urea or 25% Triton X-100 in the presence of 5.10(-4) M EDTA. After chipping off one third of the protein from the rodopsin molecule by papain treatment a significant decrease of the slope of the Arrenius curve and a maximal decrease of entropy change compared to the parameters known for heat denaturation of the pigment in native photoreceptor membranes were found. Modification of the lipid components of the photoreceptor membranes (treatment with Triton X-100 and phospholipase C) reduced the thermostability of rodopsin. Maximal changes were obtained at Triton X-100 concentrations 0.1--1%, further concentration increas (1--25%) did not lead to significant changes. Phospholipase C treatment resulted in a decrease of free energy change and an increase of entropy change without affecting entalpy changes, accompaning the heat denaturation of rodopsin. Bivalent cations (Ca2+, Mg2+) increased the termostability of rodopsin both in photoreceptor membranes and in solutions to 25% Triton X-100.
Mol Biol (Mosk)
PMID:[Modification of the retina photoreceptor membranes and temperature stability of rhodopsin]. 73 88

Ca2+-entry into intact red cells containing [32P]-ATP increases the phosphorylation of the 150 000 dalton polypeptide of the membrane. This phosphorylation occurs even in Mg2+-depleted red cells. Extracellular lanthanum applied during ATP-depletion further increases the Ca2+-induced phosphorylation. In fragmented membranes or resealed insideout vesicles (IOVs) membrane bound Mg2+ is sufficient to catalyze the phosphorylation of spectrin 2 and Band 3 polypeptides with low concentrations (less than micron of [32P]-ATP. In Ca-EDTA buffers one single polypeptide is phosphorylated which is located in the 150 000 molecular weight region. KmCa for phosphorylation is much lower (0.2 micron) than for active Ca2+ transport (40 micron) in IOVs. Lanthanum induced phosphorylation (up to 250 micron Lafree) is significantly greater than Ca2+-induced phosphorylation. Hg2+ inhibits both Ca2+ and La3+ induced phosphorylation. Ca2+-induced labelling can be rapidly "chased" by unlabelled ATP+Mg2+, but not with EGTA+Mg2+. Dephosphorylation in Ca2+ phosphorylated membranes and IOVs is significantly inhibited by La3+. It can be concluded that the mechanism of La3+ and Hg2+ inhibition of the Ca2+ pump is different in intact cells and isolated membranes or Iovs.
Mol Cell Biochem 1978 Dec 22
PMID:Phosphorylation of the Ca2+ pump intermediate in intact red cells, isolated membranes and inside-out vesicles. 74 97

The transfecting activity of linear lambda DNA is 100 times higher in calcium treated E. coli K12 (lambda i434) than in non-lysogenic strains: the levels of transfection are 1-2.10(7) and 1-2.10(5) infective centers per 1 mug of lambda DNA respectively. The high efficiency of lysogenic cells transfection is not due to the spontaneously liberated "helper" phage. Evidently, it is called forth by transfecting DNA-prophage recombination or/and by inhibition of nuclease activity in lysogenic cells. Both ring forms lambda DNA (supercoiled and open circles) show very low infectivity, if any, in calcinated cells.
Mol Gen Genet 1976 Feb 27
PMID:Dependence of transfection efficiency of calcium treated Escherichia coli cells on bacterial genotype and form of Lambda DNA. 77 16

The present work suggests that in dog thyroid tissue Ca2+ is distributed at least in two compartments (A) and (B). Compartment (A) could be the extracellular space, and extracellular binding sites for Ca2+. The uptake of Ca2+ in this compartment is increased and the release is decreased at 0 degrees C. The release is not influenced by the ionophore A23187 or by metabolic inhibitors (NaF, iodoacetate, dinitrophenol) or by thyrotropin (TSH). Compartment (B) is defined functionally as a slowly exchangeable store of Ca2+. Uptake and release from this compartment are temperature dependent. The release is accelerated by A23187 and by antimycin A, this suggests an intracellular, presumably mitochondrial, location. TSH stimulates the efflux of Ca2+ originating from the cellular compartment (B). Our data are compatible with the hypothesis that, as in other tissues, the translocations of stored intracellular calcium may be a crucial step in the activation of the thyroid cell.
Mol Cell Endocrinol
PMID:Compartmentalization and movement of calcium in the thyroid. 78 59

1. The diphosphonate, disodium etidronate (disodium ethane-1-hydroxy-1, 1-diphosphonate; (EHDP), is known to increase plasma inorganic phosphate in man. The present study examines the mechanism of this effect. 2. When EHDP was given by mouth at a dose of 80 mumol (20 mg) kg-minus 1day-minus 1, plasma phosphate was significantly increased 24 h after the first dose but did not reach its maximum value for 2-3 weeks. When the drug was stopped, plasma phosphate returned to pretreatment values within 3 weeks. 3. Urinary excretion rate of phosphate was not greatly changed during treatment with EHDP despite the large increase in plasma phosphate, suggesting an alteration in renal handling. This was examined directly by infusing phosphate and inulin in six patients off and on EDPH. 4. EHDP had no effect on glomerular filtration rate (GFR) but produced a large increase in the maximum rate of renal tubular reabsorption of phosphate (TmP). The ratio Tm,P/GFR increased from a mean value of 1.15 mmol/1 to 2.10 mmol/1 on EHDP. This increase accounted for the hyperphosphataemia. 5. The same amount of phosphate infused at the same rate produced a greater rise in plasma phosphate when patients were on EHDP than when they were not, indicating a reduced net rate of entry of phosphate into tissues other than kidney. 6. Fasting total plasma calcium concentration and urine calcium excretion rate were not significantly altered by EHDP but the ability of infused phosphate to decrease plasma calcium was diminished. 7. It is suggested that EHDP alters phosphate transport in kidney and other tissues by a mechanism which is probably independent of the known hormonal influences on phosphate metabolism.
Clin Sci Mol Med 1975 Jul
PMID:Changes in the renal and extrarenal handling of phosphate induced by disodium etidronate (EHDP) in man. 80 49

1. The bivalent cation-binding agent, cellulose phosphate, was given for 6 days to four normal subjects and six patients with latent hypoparathyroidism (diagnosed by impaired response to EDTA infusion), all of whom were on a moderately low calcium diet. 2. In normal subjects, there was a prompt and sustained fall in urinary calcium with no change in plasma calcium, indicating increased tubular reabsorption. Plasma and urinary magnesium fell, without increase in tubular reabsorption. The urinary total hydroxyproline increased and Tm,P/glomerular filtration rate fell after 2 days; these changes were transient and were consistent with a transient increase in parathyroid hormone secretion. 3. In the hypoparathyroid patients, urinary calcium fell more slowly and a fall in plasma calcium occurred in several subjects, the extent and duration of which corresponded with parathyroid status determined by EDTA infusion. Urinary conservation of calcium was impaired but plasma and urinary magnesium fell as in normal subjects. Urinary total hydroxyproline did not change and Tm,P/glomerular filtration rate fell more slowly than in the normal subjects. 4. The relative contributions of increased tubular reabsorption and reduced filtered load to calcium conservation in response to calcium depletion depend on the prevailing level of parathyroid function; the former is more important when parathyroid function is normal, the latter when parathyroid function is impaired. 5. In the detection of reduced parathyroid reserve, the assessment based on the plasma calcium response to cellulose phosphate agrees closely with the assessment based on the degree of recovery from EDTA-induced hypocalcaemia.
Clin Sci Mol Med 1975 Aug
PMID:Effect of cellulose phosphate on calcium and magnesium homeostasis: studies in normal subjects and patients with latent hypoparathyroidism. 80 50

Energy dependent calcium binding in microsomal vesicles from the longitudinal smooth muscle of the guinea pig intestine was investigated at two different temperatures (30 degrees C and 10 degrees C) and in the absence and presence of CdCl2, BaCl2 and MnCl2. The investigation was carried out to determine whether the effects of temperature and the effects of the divalent ions on microsomal calcium binding could be correlated with the effects of these interventions on the mechanical activity of the intact longitudinal fibers. A reduction in temperature from 30 degrees C to 10 degrees C inhibited both the uptake of calcium into the microsomes and the rate of release of calcium ions from the microsomes to the external medium. This exchange in temperature also slowed the rate of relaxation of the intact longitudinal muscle after it had been induced to contract with acetylcholine and subsequently allowed to relax by removing calcium ions from the bathing medium and adding 1 X 10(-3) M EGTA. The presence of CdCl2, like the reduction in temperature, decreased the uptake of calcium into the microsomal vesicles. However, the release of calcium from the microsomes was accelerated. BaCl2, produced the same effects as did CdCl2 on the uptake of calcium into microsomes but to a lesser extent. It had very little effect on the release of calcium ions from the microsomes. MnCl2 had no significant effects on either the uptake or release of calcium ions in the microsomal preparation. Both CdCl2 and MnCl2 exerted an inhibitory action on acetylcholine-induced contractile responses of the intact longitudinal fibers; whereas BaCl2 served to initiate a contractile response in the smooth muscle fibers. Thus, it would appear that the effects of a temperature change on microsomal calcium binding and on mechanical activity in intact fibers can be correlated; but the effects of CdCl2, BaCl2 and MnCl2 on these two cellular processes do not follow any consistent pattern.
Mol Cell Biochem 1975 Jul 31
PMID:Effects of temperature and inorganic ions on calcium accumulation in microsomes from intestinal smooth muscle. 80 67


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