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)

The activities of hybrid dimers of alkaline phosphatase containing two chemically modified subunits have been investigated. One hybrid species was prepared by dissociation and reconstitution of a mixture of two variants produced by chemical modification of the native enzyme with succinic anhydride and tetranitromethane, respectively. The succinyl-nitrotyrosyl hybrid was separated from the other members of the hybrid set by DEAE-Sephadex chromatography and then converted to a succinyl-aminotyrosyl hybrid by reduction of the modified tyrosine residues with sodium dithionite. A comparison of the activities of these two hybrids with the activities of the succinyl, nitrotyrosyl and aminotyrosyl derivatives has shown that either the subunits of alkaline phosphatase function independently or if the subunits turnover alternately in a reciprocating mechanism, then the intrinsic activity of each subunit must be strongly dependent on its partner subunit.
 ...
PMID:Hybrids of chemical derivatives of Escherichia coli alkaline phosphatase. 0 86

Guinea-pigs kept on a diet deficient in vitamin C showed, after 3 weeks, a marked decrease of ascorbic acid in brain and blood leucocytes as well as of the activity of alkaline phosphatase in blood plasma. Pair-fed animals did not exhibit these changes. The alpha-methyl-p-tyrosine (alpha MpT)-induced diminution of noradrenaline in the hypothalamus and the rest of the brain was attenuated in pair-fed animals, but restored in guinea-pigs deficient in ascorbic acid. The cerebral noradrenaline content (without administration of alpha MpT) showed a decrease in both pair-fed and ascorbic acid deficient animals. The noradrenaline of the heart exhibited a similar tendency. The alpha MpT-induced dopamine decrease in the striatum of ascorbic acid deficient animals was attenuated and the dopamine content (without alpha MpT administration) decreased. Pair-fed animals showed a similar tendency. The striatal concentration of homovanillic acid (HVA) was diminished in both pair-fed and ascorbic acid deficient guinea-pigs. The cerebral content of 5-hydroxyindoleacetic acid showed a decrease in pair-fed as well as in ascorbic acid deficient animals. It is concluded that ascorbic acid deficiency enhances the turnover of brain noradrenaline, whereas under-nutrition without ascorbic acid deficiency (pair-feeding) diminishes the turnover of cerebral noradrenaline, 5-hydroxytryptamine and striatal dopamine.
 ...
PMID:Cerebral monoamine metabolism in guinea-pigs with ascorbic acid deficiency. 0 59

19F nuclear magnetic resonance (NMR) spectroscopy has been used to study a fully active E. coli fluorotyrosine alkaline phosphatase. The fluorotyrosine resonances provide sensitive probes of the conformational states of the protein. They were used to follow the addition of zinc or cobalt to the apoprotein, and the titration of the protein with inorganic phosphate or the inhibitor 2-hydroxy-5-nitrobenzylphosphonate. The results indicate that 2 molecules of inorganic phosphate per dimer of alkaline phosphatase are required to complete a general conformational change in the protein involving perturbations to the environment of several tyrosines. Spectra of the cobalt enzyme indicate that on specific tyrosine per subunit may be near the metal site. The 19F NMR results, combined with the 31P NMR results in the accompanying paper, lead directly to the conclusion that dissociation of noncovalently bound inorganic phosphate from the enzyme is the rate-limiting process in enzyme catalysis at high pH. The local environment of the individual fluorotyrosines is also discussed.
 ...
PMID:Fluorine-19 nuclear magnetic resonance study of fluorotyrosine alkaline phosphatase: the influence of zinc on protein structure and a conformational change induced by phosphate binding. 0 91

Grivet monkeys infected with virulent Francisella tularensis Strain Schu S4 showed significant early changes in serum levels of trace metals, triglycerides and activities of alkaline phosphatase, lactate dehydrogenase and alpha-hydroxybutyrate dehydrogenase. Free amino acid levels decreased slightly and there was a marked increase in the phenylalanine: tyrosine ratio. Serum lysozyme activity and seromucoid levels also increased. Kanamycin therapy produced remission of overt signs but the changes in blood constituents were less readily affected. Immunization with the live vaccine strain of F. tularensis induced transient responses similar to those resulting from Schut S4 infection. Immunized monkeys subsequently challenged with the virulent Schu S4 strain showed no clinical signs or marked changes in blood constituents.
 ...
PMID:Changes in whole blood and serum components of grivet monkeys with experimental respiratory Francisella tularensis infection. 10 70

The cercariae of Eurytrema pancreaticum (Janson, 1889) possess four types of gland cells - proper cystogenic, penetration, ventral and dorsal gland cells. The secretion of ventral and dorsal gland cells is released into the tegument. The proper cystogenic gland cells are the largest and their contents serve for the formation of the cyst wall of metacercariae in the second intermediate host. The secretion of proper cystogenic gland cells contains besides neutral mucosubstances also acid mucosubstances with both carboxyl- and sulphogroups digestible with beta-glucuronidase. The secretion of penetration gland cells contains neutral mucosubstances and proteins with tyrosine, tryptophan and SS groups. The ventral gland cells contain mostly acid mucosubstances with sulphogroups, which are digested with beta-glucuronidase, and proteins with tyrosine, tryptophan and SH groups. The rudimentary dorsal gland cells contain a small amount of acid mucosubstances. The whole tegument of cercariae and the two main collecting canals of the excretory system exhibit a high alkaline phosphatase activity. The nerve ring and the main nerve truncs contain proteins with SH groups and hydrophilic lipids and exhibit a cholinesterase activity. The suckers contain a larger amount of glycogen.
 ...
PMID:Histochemistry of gland cells of Eurytrema pancreaticum cercariae. 16 44

Neurochemical and psychopharmacological studies of rats were designed to examine four hypotheses which have been proposed to account for the development of behavioral tolerance to the anticholinesterase, diisopropyl fluorophosphate (DFP). The fact that the activity of the enzymes, adenosine triphosphatase, alkaline phosphatase and cytochrome oxidase, did not change concomitantly with behavioral measures during chronic treatment with DFP suggests that nonspecific metabolic changes are unlikely mechanisms of behavioral tolerance. Similarly, a lack of change in choline acetylase activity coupled with constantly high acetylcholine levels (140%) and low cholinesterase activity (28.5%) tends to eliminate end-product inhibition of acetylcholine synthesis as a primary mechanism of tolerance to DFP. Alpha-Methyl-p-tyrosine in doses to 150 mg/kg affected the behaviors of control and DFP-treated rats to a comparable degree, offering no support for the hypothesis that a redundant adrenergic system may replace the cholinergic system during the development of tolerance to DFP. In contrast to these various negative findings, pilocarpine was less effective in suppressing the responding of rats tolerant to DFP than that of control subjects. This confirms other evidence indicating that a decreased sensitivity of cholinergic (muscarinic) receptors is one mechanism underlying the development of tolerance to DFP.
 ...
PMID:Experimental tests of hypotheses about neurochemical mechanisms underlying behavioral tolerance to the anticholinesterase, diisopropyl fluorophosphate. 16 30

A study has been made of the progress of involution of the mouse and rat mammary gland using histologic, electron microscopic, histochemical and autoradiographic methods. Particular emphasis has been placed on the morphology, metabolic alterations and activities of histochemically identifiable enzymes, and on the pharmacologic effects of lactation inhibiting agents and cytostatic drugs on lactation and involution. In order to allow a systematic investigation, involution was initiated in rats and mice by ligation of individual gland ducts at various time intervals. Both lactating glands and glands in different phases of involution were thus available in a given animal. The most important observation was that involution, which altogether takes approximately 2 weeks to be complete, involves a three-phase process, each phase being clearly distinguishable by morphologic and histochemical criteria. The first phase comprises approximately 4 days during which production of milk may be reinitiated. The second phase starts on day 5 of involution and constitutes the period of involution per se characterized by appreciable parenchymal cell degradation. The third phase, which starts around day 10, is the period of reorganization to the resting mammary gland. Early in the first phase of involution, substantial alveolar enlargement due to engorgement with milk, together with epithelial flattening, are prominent features. By day 3, the glandular contents decrease again in volume, the number of glandular cells and the constituent cytoplasmic organelles remaining unchanged during this period, except for the diminished appearance of fat droplets. In addition to normal appearing vacuoles with only occasional or sparse protein granules, giant vacuoles containing, in part, several hundred casein granules are found. Their formation appears to be due to increased stacking of granules in distended vacuoles prior to dissociation from the Golgi apparatus. In addition, however, the enhanced reactions of alP (alkaline phosphatase) and ATPase, which are found in the apical plasmalemma, are suggestive of resorptive activities. Protein particles absorbed from the glandular lumen equally appear to have a capacity for fusing into large vacuoles. The large protein granule-containing vacuoles regularly exhibit intense beta-Glu activity. This enzyme would appear to contribute actively to the degradation of excess milk during the first phase of involution. Autoradiographic studies reveal that the synthesis and release of proteins into the secretion is maintained for 3 days. While 3H-tyrosine uptake by the alveolar cells continues unchanged, the incorporation of 3H-palmitic acid into glandular lipoids, and of 3H-fucose into glandular polysaccharides is virtually blocked completely. An immediate reaction of the lipoid metabolism is also indicated by the decrease in 3HBDH activity on the first day of involution...
 ...
PMID:[Involution of the mammary gland. Enzyme histochemistry, elektron microscopy and radioautography (author's transl)]. 18 47

1. The interaction of NAD+, NADH and various nucleotide analogues with pig kidney alkaline phosphatase (orthophosphoric-monoester phosphohydrolase (alkaline optimum) EC 3.1.3.1) has been investigated by kinetic means. Some inhibitors act uncompetitively whereas others markedly increase the slopes of double reciprocal plots suggesting they have some affinity for the free enzyme. 2. The compounds seem to bind to alkaline phosphatase through interactions of their bases with a relatively non-specific region of the enzyme, although it is likely that for those nucleotides having some affinity for the free enzyme there is some attraction between the pyrophosphate backbone and the active site. 3. From studies of the effect of NAD+ and NADH on ATPase activity it was concluded that the substrate inhibition that is characteristic of the ATPase activity of alkaline phosphatase originates from binding of ATP to the site assumed to exist for NAD+ and NADH. The potentiation of NAD+-inhibition of ATPase activity by Mg-2+ is probably a result of the depletion of [ATP-4-] the true substrate. The depletion allows NAD+ to complete more effectively for the active site. 4. Binding of NADH is favoured by protonation of an enzymic group with a pK of approx. 9.0 belonging possibly to a tyrosine residue or a zinc hydrate. 5. A large entropy decrease was found to accompany the binding of NAD+ and NADH to alkaline phosphatase. This may be further evidence of an "induced-fit" mechanism previously suspected because of the synergistic inhibitory effects of adenosine and nicotinamide.
 ...
PMID:Nicotinamide-adenine dinucleotide inhibition of pig kidney alkaline phosphatase. 23 67

A histochemical and autoradiographic study of the lining intestinal epithelium of the snake Xenodon merremii is reported. The absorptive cells present neutral polysaccharides, arginine, tyrosine, tryptophan, cysteine, alkaline phosphatase, acid phosphatase, ATPase, AMPase, esterase and RNA. There are histochemical differences between the goblet cells of the small and of the large intestine. Whereas in the former predominates the neutral polysaccharides and are found arginine, tyrosine, tryptophan and cysteine, in the latter predominates the sulfated polysaccharides (confirmed by the uptake of radioactive sulfur) and no amino acids were found.
 ...
PMID:Histochemical (polysaccharides, proteins, nucleic acids and enzymes) and autoradiographic (incorporation of 35S labelled sodium sulfate) study of the epithelial intestinal cells of Xenodon merremii Wagler, 1824 (Ophidia). 40 42

Verrucose formations were found on the surface of fully developed sporocysts of E. pancreaticum Janson, 1889 at the site where the attenuated proboscis-like anterior portion widens into the posterior portion. Under these verrucose formations is always a group of gland cells. Their narrowed processes pass at a common site through the muscle layer and above this layer again slightly widen and project above the neighbouring tegument. The tegument of the verrucose formation differs from the neighbouring tegument of the sporocyst. In the cytoplasm of the gland cells there are large, spherical membrane-bound bodies containing proteins with tryptophan, tyrosine and SH groups. These bodies do not have any activity of alkaline phosphatase, acid phosphatase or nonspecific esterase. Besides these protein bodies the perinuclear cytoplasm is filled with beta glycogen particles and many cisternae of endoplasmic reticulum. The processes of these cells contain thick fibriles. The verrucose formations with the gland cells seem to serve for attachement and lysis. This function is applied not only during the development of the sporocyst, but also during its release from the site of location and penetration through the snail tissue.
 ...
PMID:Morphology, histochemistry and ultrahistochemistry of special verrucose formations in daughter sporocyst of Eurytrema pancreaticum. 64 May 22


1 2 3 4 5 6 7 8 9 10 Next >>