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Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ultraviolet difference spectra are produced by the binding of divalent metal ions to metal-free alkaline phosphatase (EC 3.1.3.1). The interaction of the apoprotein with Zn2+, Mn2+, Co2+ and Cd2+, which induce the tight binding of one phosphate ion per dimer, give distinctly different ultraviolet spectra changes from Ni2+ and Hg2+ which do not induce phosphate binding. Spectrophotometric titrations at alkaline pH of various metallo-enzymes reveal a smaller number of ionizable tyrosines and a greater stability towards alkaline denaturation in the Zn2+- and Mn2+-enzymes than in the Ni2+-, Hg2+- and apoenzymes. The Zn2+- and Mn2+-enzymes have CD spectra in the region of the aromatic transitions that are different from the CD spectra of the Ni2+-, Hg2+- and apoenzymes. Modifications of arginines with 2,3-butanedione show that a smaller number of arginine residues are modified in the Zn2+-enzyme than in the Hg2+-enzyme. The presented data indicate that alkaline phosphatase from Escherichia coli must have a well-defined conformation in order to bind phosphate. Some metal ions (i.e. Zn2+, Co2+, Mn2+ and Cd2+), when interacting with the apoenzyme, alter the conformation of the protein molecule in such a way that it is able to interact with substrate molecules, while other metal ions (i.e. Ni2+ and Hg2+) are incapable of inducing the appropriate conformational change of the apoenzyme. These findings suggest an important structural function of the first two tightly bound metal ions in enzyme.
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PMID:Metal ion-induced conformational changes in Escherichia coli alkaline phosphatase. 1 23

The activity of acid phosphatase in the testicular parenchyma of cattle was found to be higher than that in the endometrium. The acid phosphatase of either tissue broke up p-nitrophenylphosphate at a rate twice as high as that reached for di-sodium phenylphosphate. Hydrolysis of phenolphthalein diphosphate was slower and that of beta-glycerophosphate very slow. Two optimum pH values and two isozymes were recordable from acid phosphatase in testicular supernatant and three optimum pH values as well as three isozymes from that in endometrial supernatant. Even concentrations pf 0.2 mM of copper and mercury ions were strongly inhibiting the acid phosphatase, whereas lead and cadmium ions proved less effective. The activity of acid phosphatase from testes dropped by 24 per cent and that from the endometrium by 16 per cent over eight weeks of storage at -20 degrees C. The average activity of alkaline phosphatase in the endometrium was much higher than that in testicular parenchyma. Alkaline phosphatase from testes exhibited the shortest break-up time for p-nitrophenylphosphate, whereas disodium-phenylphosphate was broken up at the highest rate by endometrial alkaline phosphatase. Two isozymes of alkaline phosphatase were recordable each from the testes and endometrium.
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PMID:[Properties and isozymes of acid and alkaline phosphatase in cattle testes and endometrium]. 2 59

The rate constants which characterize the formation and breakdown of the noncovalent (E.P) and covalent (E-P) enzyme-phosphate intermediates on the alkaline phosphatase reaction pathway are known to be sensitive to the nature of the metal ion bound to the enzyme. 31P NMR saturation transfer has been demonstrated to provide a simple and sensitive method for measuring the metal ion dependence of these rates under equilibrium conditions. When the native Zn2+ was replaced by Cd2+, the 31P NMR spectrum at high pH revealed a new resonance at 12.6 ppm which has been assigned to the noncovalent enzyme.phosphate complex. Reconstituting the enzyme with enriched 113Cd2+ caused this unusually downfield-shifted resonance to appear as a doublet due to 113Cd-31P spin coupling (2J31P-O-113Cd = 30 Hz). This result provides the first unequivocal evidence for direct metal-phosphate interaction in alkaline phosphatase.
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PMID:31P NMR of alkaline phosphatase. Saturation transfer and metal-phosphorus coupling. 3 81

The non-specific phosphomonoesterase (enzyme I) extracted from the larva of the codworm (Phocanema decipiens) is different from the enzyme (enzyme II) from the muscle of its host, the codfish (Gadus morhua). The pH optima were 4.0 and 4.5, and the KM values for p-nitrophenyl phosphate hydrolysis were 1.8 mM and 6.5 mM for enzymes I and II respectively. The specific specific activity in units (0.01 mumol/min) per mg protein was 4.80 +/- 0.85 and 0.54 +/- 0.07 for enzymes I and II respectively. The specific activity from uninfected muscles was only 0.39 (SD +/- 0.017) units per mg of protein. Both enzymes were inhibited by NaF, HgCl2, and cysteine but were stimulated by 2-mercaptoethanol. EDTA and iodoacetamide had no effect on enzyme I but enzyme II was activated by EDTA and inhibited by iodoacetamide. Cadmium ions inhibited both the enzymes but a conspicuous feature with enzyme II was in the increase in percentage inhibition by lowering the concentration of CD2+.
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PMID:A comparison of the non-specific acid phosphomonoesterase activity in the larva of Phocanema decipiens (Nematoda) with that of the muscle of its host the codfish (Gadus morhua). 4 95

The marine mollusc Venus gallina was exposed to 32 days sublethal concentrations of Cadmium (0.1 microliter/ml). The activity of alkaline phosphatase was assayed every four days. In the controls the activity was also tested in different tissues and in the soft tissue for the pH dependence. Moreover the influence of direct addition of 10(-4) M Cd on enzyme preparation in vitro was assayed. From the results there are no consistent relationships between the direct in vitro effects of the metal on the enzyme, that is inhibitory, and the effect of exposing the whole animal to the same metal, in this case no inhibition was observed.
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PMID:[Effect of cadmium on the activity of alkaline phosphatase (3.1.3.1) of Venus gallina]. 4 42

Whole blood samples from 40 male and 40 female individuals were analyzed for zinc, copper, selenium and iron, and in part also for cadmium and lead. Correlations were established between the element contents and the activities of blood enzymes (carbo-anhydrase, leucine aminopeptidase, lactate dehydrogenase, alkaline phosphatase, glutathione peroxidase). The zinc-copper ratio exerted no effect on the zinc-dependent enzymes. There was a correlation between the glutathione peroxidase activity and the selenium content in whole blood (r greater than 0.73). A cluster analysis was performed. In women, the authors stated a significant effect of oral contraceptives especially on the zinc and copper balance. It was evidenced that detectable (more marked) changes in the mineral equilibrium are not produced in all cases by the contraceptives. Nevertheless, changes in the mineral equilibrium are likely to occur in 25% of all women. In the present study further changes (for example in enzymes) were observed in 50% of all women. The results obtained from the male individuals were indicative of certain relationships between the zinc-copper ratio and the content of total lipids or lipid fractions in human blood.
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PMID:[Effect of the trace element supply on element dependent enzymes in man]. 11 Nov 26

Humans are exposed to a number of toxic elements in the environment; however, most experiments with laboratory animals investigate only one toxic element. To determine if concomitant exposure to lead (Pb), cadmium (Cd), and/or arsenic (As) modified the changes produced by any one metal in various parameters of toxicity, 168 male, Sprague-Dawley, young adult rats were fed nutritionally adequate diets to which had been added 0 or 200 ppm Pb as Pb acetate, or 50 ppm Cd as Cd chloride, or 50 ppm As as sodium arsenate or arsanilic acid in a factorial design for a period of 10 weeks. At these concentrations, Cd and As reduced weight gain even when differences in food intake were taken into account; administration of both Cd and As depressed weight gain more than did either metal alone. Pb did not adversely affect food consumption or weight gain. Increased numbers of red blood cells (RBCs) were observed following administration of Pb, Cd, or As; usually more cells were observed when two or three metals were administered, compared to individual metals. Despite increasing numbers of circulating RBCs, hemoglobin and hematocrit were reduced, especially with the Pb-Cd combination and the Cd-arsanilic acid combination. Specific effects of Pb on heme synthesis were observed, including increased urinary excretion of delta-aminolevulinic acid; this increase was reduced by the presence of dietary cadmium. Analyses of blood showed values for the laboratory rat within normal ranges for blood urea nitrogen, creatinine, cholesterol, calcium, albumin, total protein, and bilirubin. Uric acid was increased by Pb, with little modification by dietary Cd or As content. Serum glutamate-oxalate transaminase activity was reduced by As. Serum alkaline phosphatase was greatly reduced by either As or Cd but not Pb. Combinations of As and Cd did not further reduce the activity of this enzyme. Kidney weight and kidney weight/body weight ratios were increased by Pb alone, with no effects of Cd or As alone or as interactions. Liver weight/body weight ratios were reduced in animals fed 50 ppm dietary Cd. Kidney histology shows predominantly Pb effects, namely, intranuclear inclusion bodies and cloudy swelling. Ultrastructural evaluation of kidneys from Pb-treated animals disclosed nuclear inclusion bodies of the usual morphology and mitochondrial swelling. Concurrent administration of Cd greatly minimized Pb effects on the kidney under conditions of this experiment. Liver histology suggests an increased rate of cell turnover with either As compound, but few specific changes.
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PMID:Effects of concurrent administration of lead, cadmium, and arsenic in the rat. 19 3

The rate of p-nitrophenyl phosphate and flavin mononucleotide (FMN) hydrolysis by the partially purified preparation of alkaline phosphatase I of Pichia guilliermondii flavinogenic yeast was studied as affected by different substrates and inorganic ions. Their Km was established to be 2.0 X 10(-4) m and 2.5 X 10(-4) M, respectively. Dephosphorylation of p-nitrophenylphosphate and FMN was inhibited competitively by beta-glycerophosphate (Ki = 3.1 X 10(-3) M, respectively). The presence of inorganic phosphate ions in the reaction mixture decreases or removes inhibition of these compounds hydrolysis by other substrates of alkaline phosphatase I. The activity of alkaline phosphatase I increases in the presence of Mg2+ and was strongly inhibited in the presence of Be2+, Cu2+, Zn2+, Cd2+ and inorganic phosphate, the mixture of Be2+ and F- being the most effective. This mixture inhibited the phosphatase activity of the partially purified preparation of alkaline phosphatase I of the cell-free extract as well as of intact cells in both the alkaline and acid zones of pH (8.6 and 5.5, respectively). Incubation of the washed iron-deficient P. guilliermondii cells in the presence of Be2+ and F- did not result in accumulation of FMN in the yeast culture. A possible role of nonspecific phosphomonoesterases in hydrolysis of FMN in vivo is discussed.
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PMID:[Inhibition of alkaline phosphatase I of Pichia guilliermondii yeast in vitro and in vivo]. 20 3

The protective and curative effects of dietary iron and ascorbic acid on chronic (180 days) cadmium toxicity in rats were examined. Growth retardation and anemia were observed in rats fed a diet containing 50 ppm of cadmium for 180 days; during this period the contents of iron in the liver, kidney, spleen, testis, intestine, and tibia decreased and the zinc contents of the liver and kidney increased, but the calcium content of bone did not change. Addition of 400 ppm of iron and 1% of ascorbic acid to the cadmium-containing diet overcame the growth retardation and anemia due to cadmium toxicity and reduced the tissue levels of cadmium; however, it did not restore the zinc contents in the liver, kidney, and bone to normal. Similar effects were observed when these compounds were added to cadmium containing diet for 90 days after feeding the cadmium diet alone for 90 days. The glutamic-pyruvic transminase and glutamic-oxaloacetic transminase activities in the plasma of rats fed the cadmium diet increased significantly and these increases were prevented by supplementing the diet with iron and ascorbic acid. Glucose, urea, and alkaline phosphatase in the plasma and glycogen in the liver were not changed by feeding the cadmium diet for 180 days. These results indicate the long-term effectiveness of supplementing the diet with iron and ascorbic-acid for preventing and curing dietary cadmium toxicity in rats.
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PMID:Long-term effectiveness of dietary iron and ascorbic acid in the prevention and cure of cadmium toxicity in rats. 21 Jun 49

The effect of vitamin D3 and dietary calcium level on the cadmium-induced changes was observed in the duodena of rats raised on various diets differing in vitamin D and calcium levels. Observation with scanning electron microscopy revealed that vitamin D and dietary calcium were required for normal intestinal villi and microvilli formation. The damaged cells were observed in the intestinal villi of cadmium-exposed rats. Furthermore, dietary cadmium reduced the enzyme activities in microvilli. Especially, alkaline phosphatase activity was reduced in the cadmium-exposed groups, even though it was still responsive to vitamin D3. These effects with cadmium were modulated by vitamin D3 and dietary calcium level. That is, in the presence of vitamin D3 and calcium, the effect of cadmium on intestinal villi and microvilli was reduced.
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PMID:The effect of vitamin D3 and dietary calcium level on the cadmium-induced morphological and biochemical changes in rat intestinal mucosa. 21 44


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