Gene/Protein Disease Symptom Drug Enzyme Compound
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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)

The aim of this study was to provide further evidence for the existence of a nonmitochondrial becarbonate-stimulated Mg2+-ATPase in brush border membranes derived from rat kidney cortex. A plasma membrane fraction rich in brush border microvilli and a mitochondrial fraction were isolated by differential centrifugation. Both fractions contain a Mg2+-ATPase activity which can be stimulated by bicarbonate. The two Mg2+-ATPases are stimulated likewise by chloride, bicarbonate, and sulfite or inhibited by oligomycin and aurovertin, though to different degrees. In contrast to these similarities, only the Mg2+-ATPase activity of the mitochondrial fraction is inhibited by atractyloside, a substance which blocks an adenine nucleotide translocator in the inner mitochondrial membrane. On the other hand, filipin, an antibiotic that complexes with cholesterol in the membranes inhibits exclusively the Mg2+-ATPase of the cholesterol-rich brush border membranes. Furthermore it could be demonstrated by the use of bromotetramisole, an inhibitor of alkaline phosphatase activity, that the Mg2+-ATPase activity in the membrane fraction is not due to the presence of the highly active alkaline phosphatase in these membranes. These results support the assumption that an intrinsic bicarbonate-stimulated Mg2+-ATPase is present in rat kidney brush border membranes.
J Membr Biol 1979 Sep
PMID:Further evidence for the existence of an intrinsic bicarbonate-stimulated Mg2+-ATPase in brush border membranes isolated from rat kidney cortex. 22 12

To distinguish between: (a) the decrease of activity of alkaline phosphatase due to inhibition by cadmium; and (b) the decline of enzyme activity due to cell destruction, 20 adult female Wistar rats were treated 3 times/week with 0.5 mg/kg CdCl2 (by subcutaneous injection) during 28 weeks. Controls received the same volume of 0.9% NaCl solution. The animals were killed at different intervals. The liver and kidneys were investigated with biochemical, histochemical, light and electron microscopical techniques. The liver homogenates show an increase of alkaline phosphatase activity after about 12-13 weeks, whereas the activity of this enzyme in the kidney decreases. This activity could not be restored by the administration of Zn ions to the medium of the enzyme assay. However, in previous in vitro experiments the Cd inhibited alkaline phosphatase activity could be totally restored by such a Zn administration. By histochemical assay of alkaline phosphatase in the renal cortex a decrease of enzyme activity was demonstrated. By evaluation of the results obtained with light and electron microscopy, in combination with the biochemical results, the decrease of alkaline phosphatase activity in the kidney should be considered as a real decrease in the amount of this enzyme due to cell degeneration.
Toxicology 1979 Sep
PMID:Influence of chronic Cd intoxication on the alkaline phosphatase activity of liver and kidney; biochemical, histochemical and histological investigations. 23 35

Pyridoxal-P reacts specifically with a single lysine residue at the active site of Escherichia coli aspartate transcarbamylase (Greenwell, P., Jewett, S. L., and Stark, G. R. (1973) J. Biol. Chem. 248, 5994-6001). Reduction of the Schiff base with sodium borohydride, succinylation of the remaining lysine residues, and digestion with trypsin result in formation of a single pyridoxyl peptide, which was purified to homogeneity after chromatography on DEAE-cellulose, treatment with alkaline phosphatase, and rechromatography. Amino acid composition and the results of limited sequential degradation showed that this peptide corresponds to residues 62 to 98 in the sequence of Konigsberg and co-workers, and contains 2 residues of lysine (Henderson, L., Roy, D., Martin, D., and Konigsberg, W., personal communication). By similar isolation, a second peptide was obtained from unsuccinylated catalytic subunit, containing only the pyridoxylated lysine, which corresponds to Lys-80. Derivatives of catalytic subunit containing an average of either one, two, or three pyridoxamine-P moieties per trimer have been prepared by reduction. These species, which retain catalytic activity in proportion to their unmodified active sites, were recombined with regulatory subunit to prepare partially modified derivatives of native aspartate transcarbamylase. At pH 8, fluorescence emission bands were observed at 340 nm, due to aromatic amino acids in the protein, and at 395 nm, due to the pyridoxamine-P moiety. Upon excitation at 280 nm energy transfer from protein to pyridoxamine-P was approximately 15%. The properties of the probe were used to study changes accompanying the binding of substrates and inhibitors. The effects of CTP and ATP were small. With the transition state analog N-(phosphonacetyl)-L-aspartate (PALA) or the substrate carbamyl-P, two types of response were observed. Derivatives of catalytic subunit and native enzyme which contain some unmodified sites and hence retain partial catalytic activity gave large increases in fluorescence at 395 nm. However, fully modified inactive derivatives gave much smaller increases. A derivative of native enzyme containing one triply modified and one unmodified catalytic subunit behaved like the other partially modified species. These results indicate that there is communication among the active sites of different catalytic trimers in modified native enzyme, as well as among active sites within the same modified catalytic trimer. The increases in fluorescence result from a red shift of the absorption maximum of the pyridoxamine-P moiety from 315 to 325 nm, which increases the absorbance at the excitation wavelength for fluorescence. At pH 7, the absorption spectrum is already shifted and, consequently, the binding of PALA and carbamyl-P has little effect on the fluorescence. Therefore, the binding of these compounds at pH 8.0 must cause a structural change in the protein, which in turn causes protonation of a group in the modified active sites, altering the spectral properties.
J Biol Chem 1975 Sep 10
PMID:Pyridoxal 5'-phosphate, a fluorescent probe in the active site of aspartate transcarbamylase. 23 51

The activities of rat intestinal enzymes, sucrase, lactase, maltase, trehalase, gamma-glutamyltransferase, leucylnaphthylamide-hydrolyzing activity, and the transport system for glucose follow diurnal rhythms on ad libitum and restricted feeding regimes. In response to 6 days of restricted feeding, food available between 1400 and 1800 Eastern Standard Time, all rhythms shifted in time and the daily levels of activities were changed. Alkaline phosphatase activity followed a diurnal rhythm only in restricted fed animals. In restricted fed rats several activity patterns were observed, some with short periods of maximum activity, 3 h or less, and some with plateaus of maximum activity, 5-9 h long. In respect to the time of day of the synchronizer, sucrase peaked before feeding, glucose transport peaked during feeding, alkaline phosphatase peaked after feeding, and the other enzymes had higher levels of activity before, during and after feeding. The effect of restricted feeding on the daily activity levels were: a decrease in leucylnaphthylamide-hydrolyzing activity, no change in alkaline phosphatase, and increases in the others. These enzyme and transport systems exhibit a large amount of individual regulation or control as reflected by the lack of a uniform activity pattern and response to the synchronizer, and the variation in direction and magnitude of the adaptations to restricted feeding.
Biochim Biophys Acta 1975 Sep 16
PMID:Effect of changes in feeding schedule on the diurnal rhythms and daily activity levels of intestinal brush border enzymes and transport systems. 24 Apr 40

56 human liver biopsy specimens with insignificant or no histological changes, but with abnormally strong canalicular alkaline phosphatase activity, were studied histochemically for other enzyme changes. In comparison with normal specimens, more extensive and increased canalicular activity of gamma-glutamyl transferase, and increase of canalicular leucine aminopeptidase, was found, while the sinusoidal activity of the latter enzyme was decreased. Staining for adenosine triphosphatase regularly desclosed the normal pattern of sinusoidal and canalicular activity. The lysosomal enzymes, acid phosphatase and beta-glucuronidase, stained more intensely than ordinarily, while the reactions for enzymes present in the cytosol (lactic dehydrogenase), in the mitochondria (succinic dehydrogenase, imonoamine oxidase) and in the endoplasmic reticulum (glucose-6-phosphatase) were normal.
Acta Pathol Microbiol Scand A 1975 Sep
PMID:On histochemical enzyme changes in association with canalicular activity of alkaline phosphatase in human liver. 24 Dec 3

Leucocyte alkaline phosphatase (LAP) was histochemically detected in 7 to 18% of cells in tissue culture lines derived from the peripheral blood or bone marrow of each of 5 patients with untreated acute myelogenous or monomyelogenous leukaemia and in 30% of the cells in a clonal line of a rat promyelocytic leukaemia. Following transfer to diffusion chambers intraperitoneally implanted into total body irradiated rats, LAP levels were detected in up to 92% of human and 80% of rat leucocytes. There was no associated morphologic differentiation. In rat leukaemia cells peroxidase and myeloid specific esterase also increased from tissue culture levels. Return of cells to tissue culture decreased enzymes to pre-implant levels. Addition of plasma or peritoneal fluid from irradiated rats to cells in tissue culture again induced LAP. In contrast, LAP was not increased under these conditions with cell lines derived from patients with acute lymphatic leukaemia, or Sezary cell leukaemia. These studies indicate that a humoral factor in peritoneal fluid and plasma of irradiated rats increases LAP in human as well as rat leucocytes.
Scand J Haematol 1977 Sep
PMID:Leucocyte alkaline phosphatase elevation in human acute leukaemia derived cell lines cultured in diffusion chambers. 26 91

Alkaline phosphatase (EC 3.1.3.1.) in developing teeth and in bone has been studied. Prior to hard tissue function a rather high enzyme activity was noted in differentiating odontoblasts, stratum intermedium, and outer enamel epithelium. A lower activity was observed in the cells of the dental papilla and stellate reticulum. After the onset of hard tissue formation the alkaline phosphatase activity was generally increased. Enzyme activity was also found in the proximal part of tall, secretory ameloblasts. In the short postsecretory ameloblasts a high enzyme activity was noted. At the onset of dentin mineralization there was an increase in enzyme activity in the cells of the subodontoblastic layer. In bone the highest alkaline phosphatase activity was found in osteoblasts. A difference was noted between the alkaline phosphatase of hard and soft tissues by means of the addition of inhibitors to the incubation media. Within the hard tissues it was possible to distinguish between two alkaline phosphatases after pretreatment with heat (56 degrees C) or the addition of specific inhibitors (sodium metavandate, ortho-and pyrophosphate). An isoenzyme which was sensitive to these procedures was demonstrated in odontoblasts and in the pulpal connective tissue. Another alkaline phosphatase isoenzyme, which was resistant to pretreatment with heat or the addition of vanadate or phosphate, was demonstrated in the subodontoblastic cell layer, stratum intermedium and the outer cells of the reduced enamel epithelium.
Scand J Dent Res 1978 Sep
PMID:Histochemical characterization of alkaline phosphatase in developing rat teeth and bone. 28 54

Calcification of the mitral ring and of the aortic valve cusps was studied in an unselected autopsy series of 219 patients over 60, dying in a department of geriatric medicine. Possible correlations with age, sex, heart size, systolic and diastolic blood pressures, bone density and serum calcium, phosphate and alkaline phosphatase were examined. There were no significant findings for aortic valve calcification though there was a weak association with advanced age. Mitral ring calcification was significantly associated with higher age, female sex and with increased heart weight after correction for body size. These findings suggest that mechanical factors, rather than changes in mineral metabolism, are implicated in the development of mitral ring calcification.
J Gerontol 1978 Sep
PMID:Valvular calcification in the elderly: possible pathogenic factors. 29 56

Two subpopulations (F4 and F6) of guinea-pig thymocytes were separated by using bovine serum albumin gradient centrifugation. The majority of F4 thymocytes were weakly alkaline phosphatase (AP) positive cells, while most of F6 thymocytes were strongly AP positive. The significant difference between their AP activities was confirmed biochemically. In the ultracytochemical study the majority of unfractionated and F6 thymocytes were light and AP positive, whereas F4 thymocytes were mostly dark, weakly AP positive cells. F4 thymocytes responded well to PHA and Con A, while F6 thymocytes failed to respond to these mitogens. The subpopulations did not differ in their homing properties. These findings indicate that strongly AP-positive cells are immature thymocytes and weakly AP-positive cells represent a more mature subpopulation of thymocytes. A hypothetical scheme for differentiation of guinea-pig thymocytes is presented.
Immunology 1977 Sep
PMID:Two subpopulations of guinea-pig thymocytes with different maturation stages. 30 22

The inhibitory effect of endogenous testosterone on parathormone induced bone changes in mice was studied with the aid of the analysis of calcium and protein content in femur and of plasma calcium and alkaline phosphatase. It was found that the absence of endogenous testosterone for seven days after castration resulted in a decrease in the bone protein and calcium content and in plasma alkaline phosphatase as compared to controls. In parathormone treated castrated mice the protein content of the femur and plasma alkaline phosphatase were raised to control values, but the decrease in the calcium content of the femur was further potentiated. Finally, the administration of parathormone to intact male mice caused only a depletion in calcium content of the femur. It may be concluded that the response of bone to parathormone is enhanced in the absence of endogenous testosterone. In view of this finding one of the possible explanations may be that endogenous testosterone protects the bone by the inhibition of its sensitivity to parathormone.
Endocrinol Exp 1978 Sep
PMID:Increased sensitivity of bone to parathyroid hormone in castrated mice. 30 90


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