Bicarbonate-stimulated ATPase activity of bovine liver alkaline phosphatase

1985 ◽  
Vol 1 (2) ◽  
pp. 167-178 ◽  
Author(s):  
Michèle Corbic ◽  
Ghislaine de Couët ◽  
Olivier Bertrand ◽  
Sylvie Cochet ◽  
Serge Erlinger
Keyword(s):  
Alkaline Phosphatase ◽  
Atpase Activity ◽  
Bovine Liver

Anion-stimulated ATPase activity of brush border from rat small intestine.

1979 ◽  
Vol 236 (1) ◽  
pp. E70 ◽  
Author(s):  
M H Humphreys ◽  
L Y Chou
Keyword(s):  
Alkaline Phosphatase ◽  
Atpase Activity ◽  
Brush Border ◽  
Atp Hydrolysis ◽  
Intestinal Transport ◽  
Mitochondrial Enzymes ◽  
Intestinal Alkaline Phosphatase ◽  
Ph Optimum ◽  
Low Concentrations ◽  
Small Intestinal

Differential centrifugation of rat small intestinal homogenates produced a crude brush border (BB) fraction that was enriched 15-fold for the marker enzymes, alkaline phosphatase and sucrase; contamination with mitochondrial enzymes, monoamine oxidase and succinate dehydrogenase, was minimal. ATP hydrolysis by this BB fraction was stimulated by addition of several anions to the incubation medium: HCO3 and Cl were equally effective in this regard, with NO3, NO2, SO4, and acetate being less stimulatory. SCN and CNO inhibited ATPase activity, whereas the divalent anion SO3 was stimulatory at low concentrations (less than 25 mM) but inhibitory at 100 mM. Maximum anion stimulation was observed at a Mg concentration of 0.5 mM, and pH optimum was 8.5. Kinetic analysis showed that HCO3 increased the Vmax without altering the Km for ATP; the Ka for this effect of HCO3 was 35 mM. This enzyme activity was completely inhibited by 20 mM L-phenylalanine, 10 mM L-cysteine, and 3 mM EDTA, compounds that also inhibited intestinal alkaline phosphatase. These results demonstrate the presence of anion-stimulated ATPase activity in rat small intestinal brush border and suggest that this activity may be related to intestinal alkaline phosphatase. The role of this enzyme in intestinal transport is not known, but could relate to the regulation of intestinal absorption and secretion.

Histochemical studies on Raillietina (Raillietina) johri (Cestoda: Davaineidae). I. Nonspecific and specific phosphatases

1979 ◽  
Vol 53 (1) ◽  
pp. 45-49 ◽  
Author(s):  
T. K. Roy
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Atpase Activity ◽  
Functional Significance ◽  
Adenosine Triphosphatase ◽  
Vas Deferens ◽  
Gland Cells ◽  
Vitelline Gland ◽  
Receptaculum Seminis ◽  
Almost All

ABSTRACTCertain phosphatases have been localized by histochemical techniques in various tissues of a pigeon cestode, Raillietina (Raillietina) johri. Acid phosphatase (AcPase), alkaline phosphatase (AlPase) and adenosine triphosphatase (ATPase) were present in almost all structures: tegument; subtegumental muscles; subtegumental cells; excretory canal; tsetes; sperm ductules; vas deferens; cirrus sac; cirrus; ovary; receptaculum seminis; vagina; vitelline gland cells; oocytes; uterus; embryonated eggs. AlPase was absent in parenchyma, spermatocytes, spermatids and spermatozoa. AlPase activity was more intense in the tegument of mature gravid proglottides. AcPase and ATPase were visualized in various stages of spermatogenesis of the parasite. ATPase activity was also observed in chromosomes. 5'-nucleotidase (AMPase) activity was restricted to embryonated eggs only. Functional significance of these phosphatases is discussed.

Anion-stimulated ATPase in locust rectal epithelium

1988 ◽  
Vol 66 (2) ◽  
pp. 431-438 ◽  
Author(s):  
R. A. Lechleitner ◽  
J. E. Phillips
Keyword(s):  
Alkaline Phosphatase ◽  
Plasma Membrane ◽  
Atpase Activity ◽  
Microsomal Fraction ◽  
Leucine Aminopeptidase ◽  
Mitochondrial Fraction ◽  
Mitochondrial Enzymes ◽  
Differential Centrifugation ◽  
Succinate Cytochrome C Reductase ◽  
Nacl Cotransport

The rectum, the main reabsorptive site in the locust excretory system, actively transports Cl−. This Cl− absorption is electrogenie, not dependent on Na+or [Formula: see text] and insensitive to inhibitors of NaCl cotransport or [Formula: see text] exchange. To determine if active Cl− transport across rectal epithelia might be due to an anion-stimulated ATPase, a microsomal fraction was obtained by differential centrifugation. Microsomal ATPase activity was stimulated in the following sequence: sulphite > bicarbonate > chloride. Maximal ATPase activity was obtained at 25 mM [Formula: see text] or 25 mM Cl−. Thiocyanate (10 mM) inhibited 90% of the anion-stimulated ATPase activity. The microsomal fraction was enriched in the plasma membrane markers, leucine aminopeptidase, alkaline phosphatase, 5′-nucleotidase, and γ-glutamyItranspeptidase, and had little contamination of the mitochondrial enzymes, succinate cytochrome c reductase and cytochrome oxidase. Na,K-ATPase was enriched in the mitochondrial fraction. Microscopic examination confirmed that basolateral membranes were associated with mitochondria following differential centrifugation, while the microsomal fraction contained little mitochondrial contamination. These results indicate the presence of an anion-stimulated ATPase activity that could be responsible for active Cl− transport across locust recta.

Phosphoester specificity of purified human liver alkaline phosphatase

1979 ◽  
Vol 57 (7) ◽  
pp. 1000-1007 ◽  
Author(s):  
L. E. Seargeant ◽  
R. A. Stinson
Keyword(s):  
Alkaline Phosphatase ◽  
Atpase Activity ◽  
Human Liver ◽  
Magnesium Ions ◽  
Calcium Dependent ◽  
Ph Values ◽  
Regulator Protein ◽  
Calcium And Magnesium ◽  
Hydrolysis Of ◽  
Calcium And Magnesium Ions

Kinetic parameters for the hydrolysis of a number of physiologically important phosphoesters by purified human liver alkaline phosphatase have been determined. The enzyme was studied at pH values of 7.0 to 10.0. The affinity of the enzyme for the compounds was determined by competition experiments and by their direct employment as substrates. Phosphodiesters and phosphonates were not hydrolysed but the latter were inhibitors. Calcium and magnesium ions inhibited the hydrolysis of ATP and PP1 and evidence is presented to show that the metal complexes of these substrates are not hydrolysed by alkaline phosphatase. A calcium-stimulated ATPase activity could not be demonstrated for the purified enzyme or the enzyme in the presence of a calcium-dependent regulator protein. Nevertheless, the influence of magnesium and calcium ions on the ATPase activity of alkaline phosphatase means that precautions must be taken when assaying for Ca2+-ATPase in the presence of alkaline phosphatase.The low substrate Km values and the hydrolysis which occurs at pH 7.4 mean that the enzyme could have a significant phosphohydrolytic role. However, liver cell phosphate concentrations, if accessible to the enzyme, are sufficient to strongly inhibit this activity.

scholarly journals Alphostatin, an inhibitor of alkaline phosphatase of bovine liver produced by Bacillus megaterium.

1989 ◽  
Vol 42 (3) ◽  
pp. 486-488 ◽  
Author(s):  
TAKAAKI AOYAGI ◽  
HAJIME MORISHIMA ◽  
KATSUHISA KOJIRI ◽  
TAKUZO YAMAMOTO ◽  
FUKIKO KOJIMA ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Bacillus Megaterium ◽  
Bovine Liver

Studies on host specificity in Paragonimus westermani: II. Histochemical and cytochemical characterization of metacercariae and worms from rats and dogs

1989 ◽  
Vol 63 (4) ◽  
pp. 315-327 ◽  
Author(s):  
Takahiro Fujino ◽  
Koichi Fukuda ◽  
Fusanori Hamajima ◽  
Yoichi Ishii
Keyword(s):  
Alkaline Phosphatase ◽  
Acid Phosphatase ◽  
Atpase Activity ◽  
Phosphatase Activity ◽  
Metabolic Activity ◽  
Acid And Alkaline Phosphatase ◽  
Excretory Bladder ◽  
Histochemical Tests ◽  
Parenchymal Cells

ABSTRACTHistochemical tests were done on newly excysted metacercariae and worms recovered from an abnormal host (rat) and the definitive host (dog) for some oxidoreductases, phosphatases and glycosidases. The results demonstrate that rat worms have enzymatic distribution and intensities more similar to those of metacercariae than to adult worms from dogs. Ultracytochemical examination of acid and alkaline phosphatase and Mg-ATPase activity was also carried out. Acid phosphatase activity occurred exceptionally in the excretory bladder and caeca of dog worms. No activity was observed in rat worms except for lysosomal granules in the tegument. Alkaline phosphatase activity was exhibited in the excretory bladder in both dog and rat worms. Mg-ATPase activity occurred in the tegument and parenchymal cells in dog worms and in the excretory bladder in rat worms. In metacercariae, little or no reaction for these enzymes was present except for Mg-ATPase activity on the excretory ducts. These observations, together with the histochemical results, indicate that metabolic activity in rat worms is higher than in metacercariae although it is strongly reduced compared with dog worms.

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