Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Isolated mesenchymal limb bud cells from day-12 mouse embryos grown at high density in organoid culture at the medium/air interphase differentiate into chondrocytes and form cartilage nodules. Upon addition of beta-glycerophosphate (beta-GP), cartilage undergoes endochondral mineralization. This beta-GP-induced mineralization was investigated by measuring the calcium content in the cultures and the activity of alkaline phosphatase (AP) in the cell mass and the medium. Calcium incorporation depended on the amount of beta-GP added. After continuous treatment, mineralization began on day 8 of the culture period and increased linearly until day 15. In long-term cultures, periodical treatment for 6 days caused an increase in mineralization the older the cultures were, but the slope of increase was proportionately less steep. Treatment at the latest period on days 19-24 resulted in a markedly reduced mineralization. After short-term treatment (48 hours), mineralization increased also the older the cultures were and proceeded during further cultivation in beta-GP-free medium. This kinetic behavior indicates a dependency of mineralization on cartilage maturation in this in vitro system. AP activity increased enormously and nearly logarithmically in the cell mass in beta-GP-free medium, whereas beta-GP treatment inhibited this drastic increase. In the medium, considerable activities of AP were also measurable from day 10 onward. It increased in beta-GP-free medium up to day 14, but was diminished after mineralization had been induced. Levamisole inhibited AP activity dose dependently when added directly to the enzyme-containing medium (100% inhibition at 10(-3) M).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinetics of beta-glycerophosphate-induced endochondral mineralization in vitro. Calcium accumulation, alkaline phosphatase activity, and effects of levamisole. 139 78

Rat calvaria (RC) cells grown in medium containing ascorbic acid form nodules of osteoid and cells. When 10 mM beta-Glycerophosphate (beta-GP) is added, the osteoid mineralizes in two phases: an initiation phase that is dependent upon alkaline phosphatase activity and a progression phase that proceeds independently of the activity of alkaline phosphatase and does not require added beta-GP (Bellows et al., Bone Miner 1991;14:27-40). The present experiments were performed to determine whether beta-GP is converted to inorganic phosphate (Pi) during the initiation phase of the mineralization process and whether increased Pi can replace beta-GP in the initiation phase. Measurements of Pi concentrations in the culture medium showed that during the first 8 h of the initiation phase of mineralization, 10 mM beta-GP was rapidly degraded resulting in Pi concentrations of 9-10 mM. The production rate of Pi from beta-GP was linear (r = 0.996) and the alkaline phosphatase activity in the same cultures indicated a potential for conversion of beta-GP to Pi that was greater than the actual conversion rate. The addition of 2-5 mM Pi in the absence of beta-GP also initiated mineralization. Mineralization initiated by either beta-GP or Pi progressed in the absence of added beta-GP or Pi. 100 microM Levamisole inhibited the initiation of beta-GP-induced mineralization and the conversion of beta-GP to Pi, but did not affect Pi-induced initiation of mineralization. The addition of 1-5 mM Pi to cultures in which mineralization had been initiated by 10 mM beta-GP had no significant effect on the progression phase of mineralization. Neither beta-BP nor Pi initiated 45Ca uptake in cultures without nodules (RC population I) and the histological appearance of the mineralized tissue in either phosphate source appeared identical. The present experiments show that beta-GP is rapidly and virtually completely degraded to Pi during the initiation phase of mineralization and that the addition of increased concentrations of Pi can replace beta-GP in the initiation phase of mineralization in the absence of non-specific 45Ca uptake or apparent cellular toxicity.
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PMID:Inorganic phosphate added exogenously or released from beta-glycerophosphate initiates mineralization of osteoid nodules in vitro. 158 3

Ascaridia galli and Heterakis gallinae obtained from the common fowl Gallus gallus were exposed to 10(-2)-10(-5)M levamisole and albendazole; both compounds caused death of the parasites in vitro. The effect of the drugs was investigated on homogenates of the treated worms. Albendazole, at 10(-2)M, inhibited oxaloacetate reduction by 67 and 53% and malate oxidation by 21 and 17% in A. galli and H. gallinae, respectively, whereas 10(-4)M levamisole completely inhibited malate dehydrogenase activity in both directions in the two parasites. Lactate dehydrogenase was not affected significantly by either anthelmintic. Aldolase activity was diminished by 57 and 32% in A. galli and H. gallinae, respectively, with 10(-4)M levamisole. Levamisole at 10(-4)M also inhibited the activity of acid and alkaline phosphomonoesterase and cholinesterase. Albendazole had no significant effect on these enzymes in either parasite. Malate dehydrogenase and cholinesterase activity of the host tissue (intestine and caecum) was also reduced significantly with 10(-2) and 10(-3)M levamisole. These studies indicated a multiple mode of action of levamisole and albendazole.
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PMID:The effect of levamisole and albendazole on some enzymes of Ascaridia galli and Heterakis gallinae. 270 87

The addition of the organic phosphate, beta-glycerophosphate, to the culture media of osteoid forming cells or tissues will induce formation of mineralized bone. The mechanisms behind this phenomenon are not clearly understood. In order to gain new understanding of organic phosphate induced mineralization of bone it was decided to attempt to inhibit this process in two fundamentally different ways. Firstly, the reversible inhibitor of alkaline phosphatase, Levamisole, was used to help define the role of alkaline phosphatase in mineralization in vitro. Secondly, inorganic pyrophosphate, a known inhibitor of hydroxyapatite (HA) formation was also used. It was hypothesized that inorganic pyrophosphate, in addition to its ability to block HA formation, might also interfere with organic phosphate access to alkaline phosphatase and thereby prevent mineralization. The data show that mineralization is blocked when alkaline phosphatase activity is inhibited by Levamisole prior to but not after osteoid maturation. Inorganic pyrophosphate blocks organic phosphate induced mineralization whether added before or after osteoid formation. Organic phosphate effects on alkaline phosphatase activity are reversed by the addition of inorganic pyrophosphate either before or after osteoid formation. These findings suggest a role for alkaline phosphatase in organic phosphate induced mineralization. The data show further that inorganic pyrophosphate may effect mineralization of bone not only by blocking apatite formation but possibly by modulating organic phosphate metabolism.
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PMID:Levamisole and inorganic pyrophosphate inhibit beta-glycerophosphate induced mineralization of bone formed in vitro. 285 49

Levamisole represents one of several new compounds that exhibit immunomodulating activity. Pharmacological data have documented a relationship between liver drug metabolism of levamisole and its subsequent immunomodulating activity. To directly investigate this relationship in a controlled manner, primary cultures of adult rat hepatocytes were treated with levamisole, and ultrastructural and biochemical effects were analyzed. Ultrastructurally, levamisole did not disrupt the cellular architecture of the hepatocytes. Biochemically, levamisole stimulated alkaline phosphatase activity and elevated microsomal cytochrome P-450 content after a 48-hr incubation. High pressure liquid chromatographic analysis of levamisole metabolites produced by cultured hepatocytes suggested the formation of a hepatocyte-specific metabolite(s) that may be associated with its immunological mode of action.
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PMID:Effects of levamisole on primary cultures of adult rat hepatocytes. 287 43

We investigated the localization of alkaline phosphatase (AP) in the peripheral and central nervous systems of the frog (Rana pipiens) and rat. In the frog sciatic nerve, AP reaction product was seen as a precipitate within caveolae and vesicular profiles of perineurial cells, and frequently filled the extracellular space. In the rat peripheral nerve, AP reaction product appeared as small tufts on the cell surfaces and within vesicular profiles of endoneurial blood vessels. AP reaction product was not detected in the rat perineurium or in endoneurial blood vessels of the frog. In the frog central nervous system, AP reaction product was detected in the arachnoid membrane adjacent to the subarachnoid space, but not in the cerebral or pial vessels, whereas in the rat it was detected in the outer arachnoid membrane and in the cerebral and pial blood vessels. Biochemical analysis indicated a sevenfold higher AP activity in the frog perineurium over the endoneurium, whereas in the rat, threefold more activity was measured in the endoneurium over the perineurium. Levamisole, an AP inhibitor, decreased the enzyme activity by 95% in rat tissues, and by 70% in frog tissues and in plasma from both animals. Similar decrements were observed cytochemically. This study suggests that: (1) the distribution of AP varies between species, but that it is always present in at least one component of the blood-brain and blood-nerve barriers, (2) because barrier tissues of the nervous system have enzymatic activity, they may biochemically modify the adjacent environment, (3) vesicular profiles and caveolae in the blood vessels and perineurium may function as microenvironments for enzymatic activity, and (4) in the rat and frog, different isozymes of AP may be present.
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PMID:Differential localization of alkaline phosphatase in barrier tissues of the frog and rat nervous systems: a cytochemical and biochemical study. 350 Jan 90

Intense alkaline phosphatase (ALPase) activity has been localized in the outer plexiform layer of the developing chick retina. To elucidate the functional significance of this enzymatic activity, we have injected an ALPase inhibitor, levamisole, into embryonic eyes on either the 13th or 15th day of incubation. The retina was fixed between the 15th and 20th day of incubation and examined by electron microscopy. Levamisole injection on the 13th day caused various morphological alterations in retinal development, including the appearance of solitary photoreceptor cells in the subretinal space as well as folding of both the outer plexiform and outer nuclear layers. Pedicles of photoreceptor cells in the outer plexiform layer displayed rather smooth configurations with a reduced number of invaginations by post-synaptic neurites. The outer plexiform layer was thinned and the neuritic extensions in this layer appeared much less developed than in the control (PBS-injected) retina. Photoreceptor outer segments were seldom observed. Besides these alterations, layers of optic fibers and ganglion cells were also affected, as shown by evidence of degeneration in the ganglion cells and thinning of the nerve-fiber layer. Injection of levamisole into day 15 embryonic eyes exerted less influence on retinal development, but some photoreceptor cells were still found in the subretinal space. Some of these observations have been reported in the retinas of aged normal animals or in retinas with hereditary or induced retinal dystrophy. It is suggested that ALPase activity in the outer plexiform layer of the developing chick retina may be important for the onset of normal development of synapses in the outer plexiform layer and differentiation of the photoreceptor cells.
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PMID:Alterations in the differentiation of chick retina caused by an intraocular injection of an alkaline phosphatase inhibitor. 380 58

A new rapid assay for inorganic pyrophosphatase has been developed and the procedure optimised for measurement of the enzyme in human neutrophils. Kinetic studies showed that the activity was optimal at pH 8.0 and was activated by Mg2+. No neutral or acid pyrophosphatase was detected. Neutrophils were homogenised in isotonic sucrose and, after low speed centrifugation the intracellular localization of pyrophosphatase was determined by analytical subcellular fractionation with sucrose density gradient centrifugation. Pyrophosphatase was shown to have a dual localization to mitochondria and cytosol. No activity could be attributed to either the endoplasmic reticulum or alkaline phosphatase-containing granules (phosphasomes). Inhibitor studies clearly show that the cytosolic and mitochondrial pyrophosphatases are due to distinct enzymes. Neutrophils were isolated from control subjects, patients with chronic granulocytic leukaemia and subjects in the third trimester of pregnancy. The specific activity (mU/mg protein) of pyrophosphatase, in contrast to that of alkaline phosphatase was similar in the three groups. Levamisole, a potent inhibitor of alkaline phosphatase had no effect on pyrophosphatase activity, confirming that this activity is not attributable to neutrophil alkaline phosphatase.
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PMID:Subcellular localization and properties of alkaline inorganic pyrophosphatase in human polymorphonuclear leucocytes. 612 Jul 71

Inosine 5'-diphosphatase (IDPase) activity was demonstrated cytochemically in the endoplasmic reticulum of rat kidney proximal tubule cells in tissue fixed by perfusion with glutaraldehyde--formaldehyde. Incubation for IDPase activity at pH 7.2 was performed with and without 0.5 mM levamisole, a potent inhibitor of alkaline phosphatase (AlkPase) (M Borgers, J Histochem Cytochem 21:812, 1973). Levamisole treatment of sections eliminated all reaction product in the brush border, but did not affect the IDPase activity the endoplasmic reticulum (ER). The ER appears as a basilar-luminal-oriented transcellular structure, suggesting a possible cellular transport route. This study supports and extends earlier observations made by others that suggest a transport role for the ER in these cells. It also emphasizes the value of thick section cytochemistry.
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PMID:Transepithelial endoplasmic reticulum in rat proximal convoluted tubule. 613 47

The cellular enzyme-linked immunospecific assay (CELISA) uses ligands conjugated to calf intestinal alkaline phosphatase to quantitate antibody bound to antigens on the surfaces of whole cells. Since the endogenous alkaline phosphatase present in many cell types contributes unwanted background noise to the assay, ways of inhibiting endogenous cellular alkaline phosphatase were investigated. We found that the endogenous alkaline phosphatase in human peripheral blood mononuclear cells was incompletely inhibited by EDTA or L-cysteine. Levamisole, however, inhibited endogenous cellular alkaline phosphatase completely without impairing the sensitivity of the CELISA. The use of levamisole is recommended for assays that use alkaline phosphatase conjugates to detect molecules on the surfaces of cells that also contain endogenous alkaline phosphatase.
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PMID:Cellular enzyme-linked immunospecific assay (CELISA). IV. Inhibition of endogenous cellular alkaline phosphatase activity. 642 29


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