Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mixed leukocyte suspensions were prepared from heparinized blood collected from healthy subjects and from patients with chronic myeloid leukemia (CML). In all the suspensions determinations were made for: zinc, by atomic absorption; granulocyte alkaline phosphatase (GAP), using the method with p-nitrophenylphosphatase; granulocyte LDH, by means of the enzymatic autoanalyser LKD 8,600. In the patients with CML, the values of zinc and of granulocyte alkaline phosphatase activity were very low while the granulocyte LDH values were higher than normal. The chromatogram of the granulocyte LDH isoenzymes on DEAE-Sephadex A50 minicolumn (0.5 X 12 cm) showed an "alpha type abnormality" revealed by the increased activity of the isoenzymes with high electrophoretic mobility LDH2 and LDH1 specific for tissues with intense oxidative phosphorylation. In the normal subjects the chromatogram of the leukocyte LDH isoenzymes showed a type M (skeletal muscle) prevalence denoting intense anaerobic glycolysis. Therefore the low zinc concentrations (0.55 micrograms mg N2 as compared with the normal 1.24 micrograms mg N2) in these patients cause the decrease of GAP activity by the lack of zinc in the active center of the enzyme and the decrease of cellular permeability thus allowing the extracellular release of granulocyte LDH.
 ...
PMID:Study of the relationship between the granulocyte LDH, alkaline phosphatase and Zn at the level of the leukocyte in patients with chronic myeloid leukemia. 346 14

The ability of alkaline phosphatase in purified preparations from human neutrophils and liver to utilize ATP or inorganic pyrophosphate as substrate depended upon the Mg2+ concentration. With pyrophosphate present (1.0 mmol/l), activity peaked at Mg2+ concentrations of 0.25 to 0.50 mmol/l and fell sharply above this. By contrast, p-nitrophenylphosphatase activity was activated with Mg2+ concentration up to 0.75 mmol/l but above this was constant to 5.0 mmol/l. Hydrolysis was abolished by L-levamisole, a specific inhibitor of alkaline phosphatase. Testing butanol extracts of neutrophils from 50 healthy subjects showed good correlation of enzyme activity with p-nitrophenylphosphate and ADP (r = 0.90), and between p-nitrophenylphosphate and pyridoxal phosphate (r = 0.96) as substrate, consistent with hydrolysis of all three phosphoesters by one enzyme. Inhibition studies yielded no evidence of a specific pyridoxal phosphatase. Alkaline phosphatase from human neutrophils has the same broad substrate specificity as other molecular forms of the human enzyme and, like other forms, has little or no activity towards phosphoesters complexed with Mg2+.
 ...
PMID:Substrate specificity of alkaline phosphatase from human polymorphonuclear leukocytes. 380 35

To characterize the biological changes which result in increased granulocyte alkaline p-nitrophenyl phosphatase activity in patients with polycythemia vera, the enzyme was purified from granule fractions of sucrose homogenates made from dextran-sedimented leukocytes of normal subjects and patients with polycythemia vera. Polycythemic blood yielded 3-10 times as much granulocyte alkaline phosphatase per 10(9) leukocytes as did normal blood. Sodium dodecyl sulfate extracts of granules were purified by DEAE-cellulose chromatography and sucrose gradient centrifugation to apparent homogeneity as judged by polycarylamide disk gel electrophoresis. Granulocyte alkaline phosphatase from normal subjects was purified 6910-fold with a 60% yield and a specific activity of 47 U/mg. Granulocyte alkaline phosphatase from polycythemic patients was purified 1.166-fold with a 50% yield and a specific activity of 70 U/mg. The two enzymes did not differ in molecular weight; both appeared to be about 160,000 daltons by sucrose gradient centrifugation. Both appeared to be zinc metalloenzymes, in that they were specifically inhibited by o-phenanthroline. Their elution requirements when adsorbed to DEAE-cellulose suggested they were lipoproteins although the content of phosphorus was below the threshold of detection. The identity of the two enzymes was suggested by immunological studies in which antibody prepared against purified polycythemia vera enzyme gave a precipitation reaction of identity with another polycythemia vera enzyme and two pools of normal enzyme. It is possible to account for the difference in alkaline phosphatase activity between the granulocytes of patients with polycythemia vera and normal subjects by differences in the quantity of enzyme synthesized.
 ...
PMID:Granulocyte alkaline phosphatase. Studies of purified enzymes from normal subjects and patients with polycythemia vera. 473 97

Fractionation of rabbit heterophil leukocyte homogenates by isopycnic centrifugation as well as by zonal sedimentation has helped to characterize further the particulate components of these cells. Four classes have been identified: (A) Large (0.5-0.8 microm) and dense (1.26) azurophil or primary granules, containing all the myeloperoxidase, one-third of the lysozyme, and a major proportion of the lysosomal acid hydrolase activities of the cells. (B) Smaller (0.25-0.40 microm) and less dense (1.23) specific or secondary granules, containing 90% of the alkaline phosphatase and the remainder of the lysozyme activities, but very little if any acid hydrolases. (C) Particles of low density (1.20), containing the remainder of the lysosomal acid hydrolases. This fraction was heterogeneous, but showed abundant small rod- or dumbbell-shaped particles of moderate electron opacity, surrounded by a single membrane (tertiary granules?). The possible origin of these lysosomes from contaminating macrophages could not be ruled out but appeared unlikely. (D) Slowly sedimenting material of very low density (1.14), made up of large, empty vesicular membrane structures, and containing 10% of the alkaline phosphatase, and all of a thiol-dependent acid p-nitrophenyl phosphatase, an enzyme clearly different from the lysosomal acid phosphatase.
 ...
PMID:Further biochemical and morphological studies of granule fractions from rabbit heterophil leukocytes. 545 43

Cytochemical techniques were used for the light and electron microscopical localization of alkaline phosphatase and potassium-dependent nitrophenyl phosphatase in the epidermal ionocytes of the Teleost Blennius sanguinolentus. The heavier deposition of the reaction products obtained with the different media was shown in the cytoplasmic surface of the labyrinth tubules, the apical vesicles and in intimate association with plasmic membranes. Both plasma membranes and intracellular activities are affected by the addition of specific inhibitors L-p-bromotetramisole oxalate and ouabain) to both complete and control media. The significance of the cytoplasmic localization of both the two enzymes is discussed with reference to current models of transepithelial ion transportation.
 ...
PMID:Ultrastructural demonstration of alkaline phosphatase (ALP) and K+-p-nitrophenyl phosphatase (K+-p-NPPase) in the epidermal ionocytes of Blennius sanguinolentus. 608 41

The ultrastructural localization of alkaline phosphatase and K+-NPPase was investigated in brain capillaries of newt by a cytochemical study using whole brain perfusion. The alkaline phosphatase activity was present in both luminal and antiluminal membranes of the endothelial cells. By contrast, the K+-NPPase was located only in antiluminal membranes of the brain capillaries. This distinct enzymatic distribution suggested that the luminal and antiluminal membranes are functionally different. The role of alkaline phosphatase and K+-NPPase in the blood brain barrier is discussed.
 ...
PMID:Cytochemical localization of alkaline phosphatase and ouabain-sensitive K+-dependent p-nitrophenylphosphatase activities in brain capillaries of the newt. 609 13

Some properties of inorganic pyrophosphatase (PPiase EC 3.6.1.1.) and para-nitrophenylphosphatase (p-NPPase EC 3.1.3.1) in the microsomal fraction of odontoblasts were investigated. The ratio of Mg2+:p-NPP and Mg2+:PPi for optimal enzyme activities was 1:1. A mutual substrate competition for PPiase and p-NPPase was described. In the presence of 0.1 mM EDTA, Mg2+ alone was not able to reactivate p-NPPase or PPiase. Instead, Zn2+ and Co2+ reactivated the PPiase, indicating they might act as cofactors for the enzyme. Mg2+ increased the PPiase activity, probably because Mg PP2-i was the true substrate for the enzyme. The diphosphonates ethane-1-hydroxy 1,1 diphosphonate (EHDP), methane diphosphonate (MDP) and dichloromethane diphosphonate (Cl2MDP) inhibited the PPiase activity.
 ...
PMID:Relationship of inorganic pyrophosphatase and para-nitrophenylphosphatase activities of alkaline phosphatase in the microsomal fraction of isolated odontoblasts. 612 84

The ultrastructural cytochemical localization of a potassium-dependent oubain-sensitive nitrophenyl phosphatase (transport ATPase) activity in human blood platelets is described. This potassium-dependent nitrophenyl phosphatase activity was not affected by 5 mM levamisole, indicating that the reaction product identified was not due to nonspecific alkaline phosphatase activity. The K+-dependent nitrophenyl phosphatase was strictly localized to the platelet plasma membrane, while the open canalicular system and dense tubular system were devoid of reaction product. In contrast, (Ca2+,Mg2+)-activated ATPase activity was predominantly localized in the open canalicular system and dense tubular system with very little cytochemical activity expressed at the plasma membrane. These data demonstrate a relative segregation of these enzymes into unique membrane compartments of the human platelet. Such data may be useful with regard to identification of purified membrane fractions from platelets and may be significant with regard to the understanding of the function(s) of the different membrane compartments of the human platelet.
 ...
PMID:Cytochemical localization of ouabain-sensitive (K+)-dependent p-nitrophenyl phosphatase (transport ATPase) in human blood platelets. 625 59

Na+,K+-ATPase was localized at the ultrastructural level in rat and rabbit kidney medulla. The cytochemical method for the K+-dependent phosphatase component of the enzyme, using p-nitrophenylphosphate (NPP) as substrate, was employed to demonstrate the distribution of Na+, K+-ATPase in tissue-chopped sections from kidneys perfusion-fixed with 1% paraformaldehyde-0.25% glutaraldehyde. In other outer medulla of rat kidney, ascending thick limbs (MATL) were sites of intense K+-dependent NPPase (K+-NPPase) activity, whereas descending thick limbs and collecting tubules were barely reactive. Although descending thin limbs (DTL) of short loop nephrons were unstained, DTL from long loop nephrons in outer medulla were sites of moderate K+-NPPase activity. In rat inner medulla, DTL and ascending thin limbs (ATL) were unreactive for K+-NPPase. In rabbit medulla, only MATL were sites of significant K+-NPPase activity. The specificity of the cytochemical localization of Na+,K+-ATPase at reactive sites in rat and rabbit kidney medulla was demonstrated by K+-dependence of reaction product deposition, localization of reaction product (precipitated phosphate hydrolyzed from NPP) to the cytoplasmic side of basolateral plasma membranes, insensitivity of the reaction to inhibitors of nonspecific alkaline phosphatase, and, in the glycoside-sensitive rabbit kidney, substantial inhibition of staining by ouabain. The observed pattern of distribution of the sodium transport enzyme in kidney medulla is particularly relevant to current models for urine concentration. The presence of substantial Na+,K+-ATPase in MATL is consistent with the putative role of this segment as the driving force for the countercurrent multiplication system in the outer medulla. The absence of significant activity in inner medullary ATL and DTL, however, implies that interstitial solute accumulation in this region probably occurs by passive processes. The localization of significant Na+,K+-ATPase in outer medullary DTL of long loop nephrons in the rat suggests that solute addition in this segment may occur in part by an active salt secretory mechanism that could ultimately contribute to the generation of inner medullary interstitial hypertonicity and urine concentration.
 ...
PMID:Ultrastructural localization of Na+,K+-ATPase in rat and rabbit kidney medulla. 627 10

A cytosolic phosphoprotein phosphatase of Mr = 95,000 purified from bovine cardiac muscle, which contains a catalytic subunit of Mr = 35,000, is known to be associated with a Mg2+-activated p-nitrophenyl phosphatase activity. We have found that the enzyme preparation is also active toward phosphotyrosyl-IgG and -casein phosphorylated by pp60v-src, the transforming gene product of Rous sarcoma virus. The properties of this phosphotyrosyl protein phosphatase activity closely resemble those of the p-nitrophenyl phosphatase activity but sharply differ from those of the phosphorylase phosphatase activity. Comparative studies of the activities of the Mr = 95,000 phosphatase, bovine kidney alkaline phosphatase, and ATP X Mg-dependent phosphatase toward phosphoseryl, phosphothreonyl, and phosphotyrosyl proteins and p-nitrophenyl phosphate under various conditions have been carried out. The results indicate that the Mr = 95,000 enzyme exhibits higher activity toward phosphoseryl and phosphothreonyl proteins than toward phosphotyrosyl proteins, while the kidney alkaline phosphatase preferentially dephosphorylates phosphotyrosyl proteins. ATP X Mg-dependent phosphatase is inactive toward phosphotyrosyl proteins.
 ...
PMID:Characterization of a phosphotyrosyl protein phosphatase activity associated with a phosphoseryl protein phosphatase of Mr = 95,000 from bovine heart. 630 59


<< Previous 1 2 3 4 5 6 7 Next >>