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)

Loss of calcium regulation across the plasma membrane of hepatocytes is responsible for irreversible cell damage by CCl4. The mode of action of colchicine in CCl4 acute liver damage is not completely understood. We followed the time courses of the changes in lipoperoxidation, the activities of liver plasma membrane Ca2(+)-ATPase, gamma-glutamyl transpeptidase and alkaline phosphatase, as well as the time courses of serum markers of liver damage in rats acutely intoxicated with CCl4. We assessed the effects of colchicine in this model and evaluated the effect of this drug on liver cytochrome P-450. Increased lipoperoxidation is the earliest and shortest lasting effect of CCl4 in the liver and is followed by a decrease in the activities of plasma membrane-bound enzymes. The alterations in serum enzymes showed a slower onset and were more protracted. Colchicine pretreatment produced a small decrease in cytochrome P-450 in the liver but completely prevented most of the changes produced by CCl4 in lipoperoxidation, liver plasma membrane enzyme activities and serum enzyme activities. We conclude that CCl4 metabolites trigger lipoperoxidation and then produce a longer lasting change in the plasma membrane, which thus allows calcium accumulation. Colchicine prevents the early mechanisms of CCl4 damage, and its effect on cytochrome P-450 perhaps plays only a contributory role.
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PMID:CCl4-induced lipoperoxidation triggers a lethal defect in the liver plasma membranes. 213 83

Bacillus subtilis membrane-bound holo-cytochrome c-550 was found to be expressed from the structural gene cloned on a plasmid vector in aerobically grown Escherichia coli and exhibited normal biochemical properties. This occurs despite the lack of endogenous cytochrome c and suggests that cytochrome c-heme lyase activity is also present in aerobic E. coli. The membrane topology of B. subtilis cytochrome c-550 was studied using fusions to alkaline phosphatase (PhoA). The results show that the heme domain (at least when fused to PhoA) can be translocated as apo-cytochrome and confirm that the N-terminal part of the cytochrome functions as both export signal and membrane anchor for the C-terminal heme domain. A model for the organisation of B. subtilis cytochrome c-550 in the cytoplasmic membrane is presented.
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PMID:Bacillus subtilis holo-cytochrome c-550 can be synthesised in aerobic Escherichia coli. 217 86

The aim of the work was to investigate functional changes of tubular cells after i.v. urography. As evidence the authors used assessment of urinary levels of membrane-bound enzymes--alkaline phosphatase (AP), gamma-glutamyl-transpeptidase, lysosomally bound enzymes N-acetyl-beta-D-glucosaminidase and its isoenzyme B and the low molecular protein, beta-2-microglobulin. The above substance were assessed in 15 patients with different nephropathies where i.v. urography was indicated. The examinations were made in 24-hour urine samples before i.v. urography and in two 24-hour samples after administration of the contrast substance. In all patients a significant rise of tubular enzyme excretion was observated as well as of beta-2-microglobulin. The greatest rise was recorded in alkaline phosphatase in the second sample after administration of the contrast substance (432% of the initial value). Beta-2-microglobulin and N-acetyl-D-glucoseaminidase rose already during the first collection period (B2M to 357% and NAG to 181% of the initial values). The authors conclude that i.v. urography made by hyperosmolar iodinated preparations (Verografin, Iodamide) significantly affects the function and integrity of the proximal tubule. The applied spectrum of examinations is suitable also for further investigations of the effect of contrast substances on cells of the proximal renal tubule.
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PMID:[Manifestations of dysfunction of the proximal tubules after intravenous urography]. 218 70

A review of immunohistology, involving the more commonly encountered fixation protocols and the use of proteolytic agents, was undertaken in an attempt to establish a method whereby cell surface immunoglobulins could be reliably demonstrated in routinely processed paraffin tissue sections. Immunoglobulin D (IgD) was selected as a suitable antigen for detection in reactive lymphoid tissues, since it is known to be present both on the cell surface and in the cytoplasm. Using the indirect immunoperoxidase technique and the alkaline phosphatase/anti-alkaline phosphatase technique as standard methods, only cytoplasmic IgD was identifiable in paraffin sections with monoclonal antibodies. However, using polyclonal antisera a technique was established in which membrane-bound IgD was also demonstrated in paraffin sections.
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PMID:Enhanced demonstration of cell surface immunoglobulins in paraffin-processed tissue. 220 75

Cells of Cryptococcus neoformans grown on xanthine or urate as the sole sources of nitrogen produced numerous, single membrane-bound organelles, deemed to be microbodies. Electron images of these structures showed positive cytochemical staining for catalase and alpha-hydroxy acid oxidase, known marker enzyme activities for microbodies. Microbodies in xanthine and urate-grown cells were cytochemically reactive for the presence of the hydrogen peroxide-producing xanthine and urate oxidases. Molybdenum and phosphorus (elements associated with the cofactor common to nitrogen scavenging enzymes) were detected in the substrate-induced microbodies by X-ray dispersive microanalysis. The single limiting membrane of the substrate-induced microbody was stained by a modified Gomori reaction for the presence of alkaline phosphatase, thereby suggesting the participation of this enzymic activity in the events associated with microbody chemistry.
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PMID:Electron cytochemical studies of Cryptococcus neoformans grown on uric acid and related sources of nitrogen. 221 35

A new chemiluminescent Southern blot procedure offers molecular biologists a safe, ultrasensitive and rapid alternative to conventional 32P-based systems. This new DNA detection system, SOUTHERN-LIGHT, has been developed by Tropix, Inc. The luminescent signal is produced from a direct chemiluminescent substrate, disodium 3-(4-methoxyspiro[1,2-dioxetane-3-2'-tricyclo-[3.3.1.1 .3,7]decan]-4-yl) phenyl phosphate (AMPPD), which decomposes upon dephosphorylation with alkaline phosphatase. SOUTHERN-LIGHT is an ultrasensitive, rapid detection kit for use with membrane-bound DNA. It is the first test kit to incorporate AMPPD. It requires no specialized equipment and results can be conveniently imaged on instant film or x-ray film within 5-60 min of exposure.
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PMID:Rapid and sensitive detection of DNA in Southern blots with chemiluminescence. 233 71

Protoplast fusion is a method for directly transferring cloned DNA from bacteria to mammalian cells at high efficiency. Here, we have used membrane-bound alkaline phosphatase as a reporter enzyme in a miniprotoplast fusion assay. This work demonstrates the principle that large numbers of protoplast fusions can be done simultaneously and successfully, to assay for an activity encoded by an expression vector. The technique described here circumvents key hurdles to expression cloning. This method does not require a highly sensitive assay or a way of separating a rare expressing cell from the mixture of transfected cells containing other transfected genes. With a strong promoter, the protein encoded by the undiluted transfected cDNA should be produced at at least as high a level as it is endogenously produced in the cell from which its activity was first detected. Reference clones are stored, avoiding the need to separate out the cells that are successfully transfected; this also avoids the need to repurify the DNA from the transfected cell. Because of the use of microtiter plates, it is likely that such a method could be partially automated for many types of assays.
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PMID:Protoplast fusion in microtiter plates for expression cloning in mammalian cells: demonstration of feasibility using membrane-bound alkaline phosphatase as a reporter enzyme. 233 73

Suckling rat intestine contains 35 and 65% of the cytosolic and membrane-bound alkaline phosphatase (AP) activities. The corresponding values for sucrase were 20 and 80% respectively. The amount of the soluble enzymes was reduced to 7-11% in adult rat intestine. Administration of cortisone, thyroxine or insulin to suckling animals induced adult type distribution of the enzymes. There were apparent differences in kinetic characteristics of soluble and brush border enzymes, but the kinetic properties of the normally developed and hormone-induced AP and sucrase were essentially similar. This suggested identical nature of these enzymes under these conditions. A biphasic Arrhenius plot was obtained for AP in weaned and hormone injected pups with a break point around 18 degrees C, while the soluble enzyme yielded a monophasic curve (Ea = 8-11 kcal/mole). Arrhenius plot for sucrase was monophasic in the suckling, hormone-injected and adult rat intestine (Ea = 8.3-15.1 kcal/mole). Membrane-bound enzymes were generally labile, while soluble enzyme activities were stable to heat treatment (sucrase at 50 degrees C and AP at 60 degrees C) in various experimental groups.
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PMID:Kinetic characteristics of soluble and brush border alkaline phosphatase and sucrase activities in developing rat intestine: effect of hormones. 235 52

In the midgut tissue of the silkworm, Bombyx mori, alkaline phosphatase isozymes, membrane-bound (m-ALP) and soluble (s-ALP) forms are controlled by non-allelic genes on the same chromosome. We purified and characterized both ALPs to elucidate their possible functions and to compare with mammalian ALPs. Both forms were found to be similar Mr = 68,000 in gel permeation chromatography and as a single subunit as a monomer in SDS-polyacrylamide gel electrophoresis with Mr = 58,000 for m-ALP and Mr = 61,000 for s-ALP. The pH optima of ALPs were 10.9 (m-ALP) and 9.8 (s-ALP), and the former was extremely stable even in pH 10-12 which accords with the physiological milieu in Bombyx midgut lumen. Both ALPs had similar substrate specificities. L-cysteine inhibited strongly both ALPs, but inhibitory effects of L-phenylalanine, L-homoarginine, and L-leucine were undetectable for s-ALP and very weak for m-ALP. The antibody raised against purified m-ALP recognized m-ALP but not purified s-ALP and vice versa. Rocket-immunoassay showed that m-ALP was distributed in similar levels along the length of midgut except for the most anterior portion. Seventy percent of s-ALP activity existed in the last one-third of midgut. Immunohistochemical study revealed that the m-ALP was localized at the brush border of columnar cells in the middle and posterior midgut epithelia. In contrast, the s-ALP was localized at the apical surface of goblet cells through the length of midgut. We detected ATPase activity in the purified s-ALP preparation; Mg2+ was essential for the ATPase activity and the activity also increased with KHCO3 but not with KCl. The solubilization test of m- ALP with various agents was attempted and the relationship between m-ALP and the digestive fluid-ALP was discussed.
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PMID:Genetically defined membrane-bound and soluble alkaline phosphatases of the silkworm: their discrete localization and properties. 239 71

The effects of various types of dietary fat on brush border membrane-bound enzymes in rat intestinal mucosa were examined. Four groups of five rats were pair-fed defined diets for 10 d. The control group was fed a diet containing 57% sucrose and 2% corn oil as a fixed carbohydrate reference; the three experimental groups received diets containing 57% sucrose and 2% corn oil plus 13% fat in the form of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) (either lard as a highly saturated fat or corn oil as a highly unsaturated fat). Feeding LCT compared to the control diet, decreased sucrase activity in mucosal brush borders of the duodenum and jejunum. In these segments of MCT-fed rats, sucrase activity was similar to that in the control animals. In another experiment, measuring immunoreactive sucrase-isomaltase in jejunal brush border membranes revealed that feeding a high corn oil diet, but not a high MCT diet, led to a reduction in the sucrase catalytic activity per unit weight of enzyme protein, suggesting that the degradation status of sucrase-isomaltase might be altered by the different types of dietary fats. With MCT feeding, jejunal alkaline phosphatase activity was enhanced to a large extent compared to the activity in other groups. Feeding MCT, compared to lard or corn oil, also increased microvillus phospholipids of the jejunal mucosa. These results suggest that MCT, unlike LCT, do not suppress the activity of mucosal microvillus membrane enzymes in rat small intestine.
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PMID:Effects of medium-chain triglycerides on brush border membrane-bound enzyme activity in rat small intestine. 239 18


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