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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)

1. A study of variations in experimental error of velocity measurement with substrate concentration for alkaline phosphatase reveals that the standard error is not constant or strictly proportional to velocity, but obeys a more complex dependence. 2. By using an approach based on error estimates at each individual substrate concentration, we show that the double-reciprocal plots in general are curved, necessitating a high-degree rate equation. The curves are analysed according to a recent classification of possible curve shapes for the 3:3 function, which is shown to be the lowest-degree rate equation satisfying the experimental data. 4. Other workers have supposed the enzyme to follow Michaelis-Menten kinetics, and it is shown that this assumption is approximately true at low temperatures in the absence of phosphate. 5. A study of the effects of phosphate concentration, pH and temperature on the kinetics shows that there is a gradual alteration in curve shape with these experimental variables, resulting in an apparent reduction in degree under certain special conditions, and particularly at low temperature. 6. It is shown that the steady-state kinetics do not require a flip-flop or half-of-sites reactivity mechanism as claimed, and a mechanism is proposed, a rate equation calculated and an analysis attempted. 7. An analysis of the product-inhibition effects for a linked two-sited Uni Bi enzyme is given. Alterations of asymptotic double-reciprocal slopes and limiting (1/nu) intercepts with products is discussed, and it is shown how the theory of product inhibition can be extended to complex kinetic situations to extract information as to molecular mechanism. 8. Deviations from Michaelis-Menten kinetics are expressed in terms of the magnitude of the appropriate Sylvester resultants.
Biochem J 1977 Dec 01
PMID:Steady-state kinetic studies of the negative co-operativity and flip-flop mechanism for Escherichia coli alkaline phosphatase. 2 64

Homogenates of human polymorphonuclear leucocytes (granulocytes) contain a Ca2+-dependent phospholipase A with optimal activity pH7.0. This enzyme is membrane-bound and is enriched in crude cytoplasmic-granule fraction. Ratezonal centrifugation of the cytoplasmic-granule fraction demonstrates that the phospholipase A is associated not only with specific- and azurophilic-granule populations but also with an 'empty' vesicular fraction containing 85% of the total alkaline phosphatase activity of whole homogenate. Thus this phospholipase is associated with granule as well as with other cellular membranes of human granulocytes.
Biochem J 1977 Dec 01
PMID:Phospholipase A activity associated with membranes of human polymorphonuclear leucocytes. 2 68

The clinical and biochemical response to 25-hydroxycholecalciferol (25-HCC) and vitamin D3, 150 microgram/day for 20 days has been compared in infants aged 3--18 months with nutritional rickets. The infants were allocated at random to Group I (11 infants) treated with 25HCC and Group II (9 infants) treated with vitamin D3. In addition 15 matched control children without rickets were allocated to Group III and received 25-HCC 75 microgram/day for 20 days. Preliminary studies showed that plasma calcium, phosphorus, alkaline phosphatase and urine pH all differed significantly between the rachitic and control groups. The biochemical parameters in both groups of rachitic children became normal after treatment with the exception of plasma alkaline phosphatase which remained elevated. The control group showed a significant increase in plasma and urine calcium values in spite of the low dose of 25-HCC. The findings suggest that 25-HCC is as effective as vitamin D3 in the treatment of rickets but did not demonstrate any therapeutic advantage.
Eur J Pediatr 1977 Dec 30
PMID:Therapeutic and collateral effects of 25-hydroxycholecalciferol in vitamin D deficiency. 2 50

Alkaline phosphatase from calf intestine (orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1) is reversibly inhibited at pH 8.0 by incubation with chelating agents. Complete reactivation may be achieved by stoichiometric addition of Zn2+. Atomic absorption spectrometry was used to demonstrate the linear correlation between Zn2+ content and degree of reactivation. The reversibly inhibited enzyme contained 1 Zn2+ per subunit whereas 2 Zn2+ were found in both the reactivated and the native enzyme. At more alkaline pH-values, inactivation by chelating agents becomes irreversible; under such conditions the inactivated alkaline phosphatase still contains 1 Zn2+ per subunit. The conformational changes resulting from the loss of Zn2+ and leading to irreversible inactivation were investigated by optical rotatory dispersion, immunological techniques, and ultraviolet and fluorescence spectroscopy. Azocoupling of the alkaline phosphatase with diazonium-1-H-tetrazole and Zn2+ content measurement of azocoupled enzyme probes indicated that 2 histidine residues per subunit are involved in binding of the catalytically important Zn2+.
Biochim Biophys Acta 1978 Dec 08
PMID:The role of Zn(II) in calf intestinal alkaline phosphatase studied by the influence of chelating agents and chemical modification of histidine residues. 3 15

Individual heritability and differences in the concentration of the chemical components of the blood were studied in the dairy cows of the Slovak Spotted breed. The experiment was performed with 166 cows. The set comprised six groups of half-sisters from three stocks. The differences among the cows were statistically significant (alpha = 0.01) in the majority of the parameters studied: haematocrit, haemoglobin, pH, PO2, oxygen saturation of the blood; plasma potassium, phosphorus, magnesium, calcium, total protein, urea, glucose, alkaline phosphatase, and esterified fatty acids. The coefficients of repeatibility for the mentioned parameters ranged from 0.19 to 0.75. The heritability coefficients were calculated for the parameters in which the inter-group differences were significant: total protein (0.62), magnesium (0.57), potassium (0.51), urea (0.49), glucose (0.45), phosphorus (0.43), calcium (0.39), haematocrit (0.37), haemoglobin (0.35), pO2 (0.29). The results suggest that some of the parameters under study are under certain genetic control.
Vet Med (Praha) 1978 Dec
PMID:[Genetically conditioned variability of metabolic profile parameters in dairy cows]. 3 53

By means of DEAE-Sephadex A-50 Column chromatography, Trimeresurus gramineus venom was separated into twelve fractions. The fibrinogenolytic activities were distributed in Fractions 1 and 10. These enzymes were further purified by gel filtration and were homogeneous as judged by cellulose acetate membrane, sodium dodecyl sulfate polyacrylamide gel electrophoresis and ultracentrifugal analysis. Both of them were single peptide chains. The sedimentation constants of alpha- (Fraction 1) and beta-fibrinogenases (Fraction 10) were 2.20 and 3.60, respectively. The molecular weights of alpha- and beta-fibrinogenases were 23 500 and 25 000 respectively. The contents of proline and glycine were higher in beta-fibrinogenase than in alpha-fibrinogenase. The isoelectric points of alpha-fibrinogenase and beta-fibrinogenase were pH greater than 10 and 4.5, respectively. The optimal pH of alpha-fibrinogenase was approx. 7.4 and that of beta-fibrinogenase was approx. 9.0. The activity of alpha-fibrinogenase was completely destroyed after 30 min at 60 degrees C, pH 5.4, 7.4 and 9.0, while that of beta-fibrinogenase was much less affected by the same treatment. The specific fibrinogenolytic activity alpha-fibrinogenase was 31 mg fibrinogen/min per mg protein, while that of beta-fibrinogenase was 9 mg fibrinogen/min per mg protein. alpha-Fibrinogenase cleaved specifically the alpha(A) chain of monomeric fibrinogen without cleaving the beta(B) chain and gamma-chain. beta-fibrinogenase preferentially cleaved the beta(B) chain, and the alpha(A) chain was also partially cleaved by beta-fibrinogenase, if the incubation time was prolonged. Both enzymes showed proteolytic activities toward fibrinogen, fibrin and casein, but were devoid of phospholipase A, alkaline phosphomonoesterase and phosphodiesterase activities found in the crude venom. The tosyl-L-arginine methylester esterase activity of beta-fibrinogenase was about 14 times that of crude venom, while alpha-fibrinogenase was completely devoid of this activity. The fibrinogenolytic activity of alpha-fibrinogenase was markedly inhibited by EDTA and cysteine, while that of beta-fibrinogenase was inhibited markedly by phenylmethanesulfonylfluoride. alpha- and beta-fibrinogenases exert their fibrinogenolytic activity by a direct action on fibrinogen or fibrin without activation of plasminogen.
Biochim Biophys Acta 1979 Dec 07
PMID:Alpha and beta-fibrinogenases from Trimeresurus gramineus snake venom. 4 82

We have determined the distribution in cord blood from healthy newborns of six enzymes: creatine kinase, lactate dehydrogenase, aspartate and alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase. The concentration of enzymes were determined according to the methods recommended by the Scandinavian Committee on Enzymes. The distribution of isoenzymes and of enzymes in blood from women at delivery was investigated also. All distributions were positively skewed. The upper reference limits of cord blood exceeded those found in mother blood by a factor of eight for gamma-glutamyltransferase, and for lactate dehydrogenase and creatine kinase by a factor of two.
Scand J Clin Lab Invest 1979 Dec
PMID:Reference values for six enzymes in plasma from newborns and women at delivery. 4 84

The marked renin inactivation seen during in vitro incubation of post-partum uterine slices which mimics the in vivo condition, is not accompanied by a similar general proteolysis. The inactivating mechanism is so far non-specific with respect to organ or species as added hog renal renin is inactivated at a similar rate as endogenous renin. Endogenous alkaline phosphatase is not significantly inactivated and added alkaline phosphatase is completely stable. A marked inactivation of endogenous renin also takes place during incubation of a mixed mitochondrial-lysosomal suspension prepared from post-partum uterus. The process is more pronounced at pH 7.4 than at 6.8. Freezing and thawing and addition of Triton X-100 prior to incubation inhibits the inactivation. ATP and alpha-ketoglutarate slightly stimulates the process while CoA and chloroquine have no effect. Both iodoacetate and phenylmethylsulphonylfluoride inhibit the inactivation, suggesting that more than one enzyme is involved in the inactivation.
Acta Endocrinol (Copenh) 1979 Dec
PMID:Inactivation of renin in a mixed mitochondrial-lysosomal fraction of post-partum uterus. 4 45

The activities of alkaline phosphatase (AP), gamma-glutamyl-transpeptidase and leucine aminopeptidase as well as the total bile salt concentration (Tbs) were measured in bile specimens collected spontaneously at 7 and 11 a.m. and 4 and 9 p.m. from the 3rd-9th postoperative day of 16 patients with T-tube insertion. The general trend for all cholestatic enzymes to increase or decrease was in some way related to the total bile salt concentration. The best correlation was found between AP and Tbs (r = 0.48). It is suggested that the enterohepatic circulation of bile salts may lead to the delivery of membrane-bound cholestatic enzymes into the bile canaliculi without damage to the hepatocyte.
Clin Biochem 1979 Dec
PMID:Daily fluctuation of cholestatic enzymes in bile and its relationship to the total bile salts concentration. 4 82

A prospective study of 181 patients suspected of having liver disease was carried out to determine the relative efficiencies of serum bilirubin (total and direct), alkaline phosphatase (AP), gamma glutamyl transferase (GGT), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) with respect to diagnosis. Liver biopsies, liver scans, abdominal ultrasound, and clinical parameters were also tabulated and used independently to evaluate the patient's hepatic status and to determine the final diagnoses in each case. From the results of these tests for the 60 patients who were diagnosed as having liver disease, and the 87 patients who were felt to be free of liver disease, predictive values of the above tests were established. Data from this study suggests that while direct bilirubin is the most specific test, GGT is the most sensitive and has the fewest false negatives in the diagnosis of liver disease.
Clin Biochem 1979 Dec
PMID:Predictive values of various liver function tests with respect to the diagnosis of liver disease. 4 85


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