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)

Purified phosphodiesterase-phosphomonoesterase was found to be composed of four isozymes with different isoelectric points. These isozymes, phosphodiesterase-phosphomonoesterases 1-4, were separated from one another by repeated isoelectric focusing. Very little difference in amino acid composition, enzymic properties or circular dichroism spectra was detected among the isozymes. Far-ultraviolet circular dichroism spectra showed that the enzyme contained about 10% alpha-helix and 40% beta-structure. Phosphodiesterase-phosphomonesterase is a glycoprotein, because it was adsorbed on concanavalin A-Sepharose 4B and gave a band of carbohydrate coincident with that of protein or enzymic activity on polyacrylamide disc gel electrophoresis. Carbohydrate analyses revealed that the enzyme contained 37 micron of N-acetylglucosamine and 358 micron of mannose per mg of protein. The carbohydrate contents of the four isozymes were almost the same.
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PMID:Phosphodiesterase-phosphomonesterases from Fusarium moniliforme. Separation and properties of four isozymes. 21 23

The mechanisms for transport and hydrolysis of lactose were investigated in five cariogenic strains (HS6, AHT, FA1, NCTC 10449, and SL1) representing the four serogenetic groups of Streptococcus mutans. The systems for transport and hydrolysis of lactose had the characteristics of a phosphoenolpyruvate (PEP)-dependent lactose (Lac) phosphotransferase (PT) system and phospho-beta-galactosidase (P-beta-gal), respectively, in all strains tested, except strain HS6. Decryptified cells required PEP and Mg(2+) for transport of the non-metabolizable model beta-galactosides o-nitrophenyl-beta-d-galactopyranoside (ONPG) and thiomethyl-beta-d-galactopyranoside (TMG). Substitution of 2-phosphoglycerate (2-PG) for PEP also stimulated the Lac PT system. Other potential high-energy phosphate donors (adenosine tri-, di-, and monophosphates and guanosine triphosphate) did not stimulate the Lac PT system. Sodium fluoride had no effect upon the PEP-dependent Lac PT system in decryptified cells with PEP as the energy source; however, when 2-PG was used as the energy source, F(-) inhibited ONPG phosphorylation. With intact cells which must generate PEP endogenously, the presence of F(-) in concentration >/= 10 mM completely inhibited the Lac PT system, presumably through inhibition of 2-PG hydrolyase (EC 4.2.1.11; enolase). Both intact and decryptified cells accumulated a phosphorylated derivative of TMG that behaved chromatographically as TMG-phosphate. After alkaline phosphatase treatment, the derivative had an R(f) identical to that of TMG. No beta-galactosidase (beta-gal) activity was detected with ONPG as the substrate; hydrolysis occurred only when ONPG-6-phosphate was supplied as the substrate. Strain HS6 apparently transported lactose by an active transport-type system in which the accumulated intracellular product was the free disaccharide based on the following criteria: (i) ONPG transport and hydrolysis in decryptified cells was not stimulated by PEP; (ii) ONPG hydrolysis occurred in the absence of PEP; and (iii) ONPG-6-phosphate was not hydrolyzed. These data indicate that, in all strains tested except strain HS6, lactose transport was mediated by a PEP-dependent Lac PT system, resulting in accumulation of lactose-phosphate that was hydrolyzed by an enzyme similar to the P-beta-gal of group N streptococci and Staphylococcus aureus; conversely, strain HS6 transported and hydrolyzed lactose by a PEP-independent transport system and beta-gal, respectively.
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PMID:Involvement of phosphoenolpyruvate in the catabolism of caries-conducive disaccharides by Streptococcus mutans: lactose transport. 24 29

Human beta-glucuronidase (beta-D-glucuronide glucuronosohydrolase, EC 3.2.1.31), like many other glycoprotein lysosomal hydrolases, is specifically taken up from the culture medium by human fibroblasts. Prior work has indicated that the enzyme exhibits charge heterogeneity and that "high-uptake" forms, i.e., those rapidly internalized by human fibroblasts, are more acidic than slowly internalized forms. Here we present two lines of evidence that the acidic group required for the high-uptake property of certain forms of the enzyme is a phosphate on, or in proximity to, a D-mannose-type carbohydrate. The first line of evidence was obtained from analysis of inhibition of enzyme pinocytosis by yeast mannans, phosphorylated sugars, and sugars. Mannans that contained phosphate were more potent inhibitors than those that did not contain phosphate. D-Mannose 6-phosphate was a more potent inhibitor than either D-mannose 1 phosphate or 2-deoxy-D-glucose 6-phosphate. D-Mannose and certain related sugars were weak pinocytosis inhibitors, while 2- and 4-epimers of mannose were noninhibitory. Competitive inhibition was demonstrated and the apparent Kis estimated for the following compounds: Saccharomyces cerevisiae mannan from mutant X2180-mnnl, 3 X 10(-6) M; mannan from wild-type S. cerebisiae, 3 X 10(-5) M; D-mannose 6-phosphate, 6 X 10(-5) M; L-fucose, 4 X 10(-2) M; and D-mannose, 6 X 10(-2) M. The second line of evidence comes from the observation that alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] treatment of human platelet beta-glucuronidase abolished its "high-uptake" activity, without diminishing its catalytic activity, and converted some forms of the heterogeneous enzyme to less acidic forms.
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PMID:Phosphohexosyl components of a lysosomal enzyme are recognized by pinocytosis receptors on human fibroblasts. 26 21

The receptor specificity of the plant seed toxin ricin, which ordinarily binds to galactose-containing receptors, has been altered by coupling monophosphopentamannose residues to ricin by reductive amination and by reversibly binding lactose to the modified ricin. The added monophosphopentamannose residues provide ricin with the recognition factor common to fibroblast lysosomal hydrolases and enable the modified ricin (Man6P-ricin) to bind to the fibroblast Man6P receptor and inhibit protein synthesis in the cells via this receptor. The addition of lactose to Man6P-ricin saturates the galactose site on Man6P-ricin and prevents the binding of Man6P-ricin to cells via galactose-containing ricin receptors. The Man6P receptor-mediated toxicity of Man6P-ricin, identified in human fibroblasts by competition by Man6P and blockade by alkaline phosphatase treatment, was not detected in HeLa cells or human amnion cells. Consequently, in the presence of lactose, the fibroblasts were 8 and 13 times more sensitive than amnion and HeLa cells, respectively. These results show that highly toxic cell-type-specific reagents can be made by the proper alteration of toxin receptor specificities. An attempt to construct a highly toxic altered toxin by adding Man6P residues to diphtheria toxin fragment A was unsuccessful. A possible explanation is that in Man6P-ricin the ricin B chain performs some entry function, even though the initial binding step occurs at the Man6P receptor.
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PMID:Ricin linked to monophosphopentamannose binds to fibroblast lysosomal hydrolase receptors, resulting in a cell-type-specific toxin. 29 62

Adsorptive endocytosis of lysosomal enzymes by fibroblasts and hepatocytes involves binding to cell surface receptors that recognize on lysosomal enzymes a phosphorylated carbohydrate, most likely a mannose 6-phosphate residue [Kaplan et al. (1977) Proc. Natl Acad. Sci. U.S.A. 74, 2026-2030; Ullrich et al. (1978) Hoppe-Seyler's Z. Physiol. Chem. 359, 1591-1598]. Loss of alpha-N-acetylglucosaminidase endocytosis after treatment with endoglucosaminidase H indicated that the recognition site of alpha-N-acetylglucosaminidase is located on N-glycosidically linked oligosaccharides of the high mannose type. Acidic oligosaccharides with an average molecular weight of 2200 were liberated from alpha-N-acetylglucosaminidase by endoglucosaminidase H. These oligosaccharides were susceptible to degradation by alkaline phosphatase, alpha-mannosidase and beta-N-acetylglucosaminidase. At the non-reducing terminal these oligosaccharides bear phosphorylated mannose and/or N-acetylglucosamine residues.
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PMID:Isolation and characterization of phosphorylated oligosaccharides from alpha-N-acetylglucosaminidase that are recognized by cell-surface receptors. 42 91

Brush border sucrase and alkaline phosphatase activities are considerably enhanced in the intestine of ascorbic acid deficient guinea-pigs. Similar increase in the uptake of D-glucose and L-alanine also occurs in chronic vitamin C deficiency. However the permeability of D-glucose and L-alanine in the intestine of animals fed with large doses of vitamin C is severely depressed, with a reduction in the levels of sucrase and alkaline phosphatase activities.
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PMID:Effect of chronic hypo and hypervitaminosis C on the brush border enzymes and the intestinal uptake of glucose and alanine. 47 73

The nonspecific alkaline phosphatase of yeast (Saccharomyces strain 1710) has been purified by ion exchange, hydrophobic, and affinity chromatography. This vacuolar enzyme has a molecular weight of 130,000 and is composed of subunits (probably of 66,000 molecular weight). It also has a small quantity of covalently associated carbohydrate; hydrolysis yielded mannose and glucosamine. The endo-beta-N-acetylglucosaminidase of Streptomyces plicatus released carbohydrate indicating that the latter was attached to protein through an N-acetylglucosaminylasparginyl bond. Synthesis of active alkaline phosphatase by yeast protoplasts is not depressed by tunicamycin, an inhibitor of dolichol-mediated protein glycosylation. Unlike the enzyme normally produced, the alkaline phosphatase which is formed in the presence of the antibiotic does not interact with concanavalin A and, therefore is deficient in or lacking carbohydrate. We infer that there is no regulatory link in yeast between the glycosylation of a protein and its synthesis. The fact that other Asn-GlcNAc-type glycoprotein enzymes of yeast such as acid phosphatase are not produced in their active forms by tunicamycin-treated protoplasts may mean that, as unglycosylated proteins, they cannot be correctly folded or processed. Protoplasts derepressed for phosphatase production contained substantial amounts of a second alkaline phosphatase which differed from the purified enzyme in substrate specificity, sensitivity to calcium, and reactivity with concanavalin A.
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PMID:Glycoprotein nature of yeast alkaline phosphatase. Formation of active enzyme in the presence of tunicamycin. 50 Jun 84

Octyl beta-D-glucoside was synthetized from alpha-acetobromoglucose with an improved method yielding a very pure product with a sharp melting point (108-109 degrees C) and free of intermediate products as judged by IR and NMR spectra. The yield of the synthesis is 66% when referred to alpha-acetobromoglucose. The potency of this compound as a detergent on hog kidney brush border membranes was compared to the action of Triton X-100. Octyl glucoside preferentially extracts aminopeptidase M and gamma-glutamyltranspeptidase in a concentration-dependent manner. The more deeply imbedded membrane enzyme, alkaline phosphatase, was relatively resistent to the action of octyl glucoside. In contrast, Triton X-100 extracted all membrane proteins to about the same extent. Additionally it was found that octyl glucoside can be removed from membrane extracts by Biobead SM 2. The capacity of the beads is about 170 mg detergent/g of dry Biobead SM 2. Thus octyl glucoside seems to be a useful tool for solubilization and purification of brush border membranes proteins.
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PMID:The use of octyl beta-D-glucoside as detergent for hog kidney brush border membrane. 54 35

Receptor-mediated endocytosis of alpha-N-acetylglucosaminidase by cultured epithelial rat liver cells is inhibited by mannose, L-fucose and most effectively by mannose 6-phosphate. Endocytosis of alpha-N-acetylglucosaminidase is lost after treatment of the enzyme with alkaline phosphatase. These findings indicate that epithelial rat liver cells possess cell surface receptors that recognize a phosphorylated carbohydrate on alpha-N-acetylglucosaminidase, as was previously reported for cell surface receptors of human skin fibroblasts. Inhibition of alpha-mannosidase endocytosis by epithelial rat liver cells in the presence of mannose 6-phosphate and loss of enzyme endocytosis after treatment with alkaline phosphatase suggest that this enzyme is recognized by the same receptor.
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PMID:Epithelial rat liver cells have cell surface receptors recognizing a phosphorylated carbohydrate on lysosomal enzymes. 56 30

Adsorptive endocytosis of five different lysosomal enzymes from various human and non-human sources was susceptible to inhibition by mannose and l-fucose, methyl alpha-d-mannoside, alpha-anomeric p-nitrophenyl glycosides of mannose and l-fucose, mannose 6-phosphate and fructose 1-phosphate. A few exceptions from this general scheme were observed for particular enzymes, particularly for beta-glucuronidase from human urine. The inhibition of alpha-N-acetylglucosaminidase endocytosis by mannose, p-nitrophenyl alpha-d-mannoside and mannose 6-phosphate was shown to be competitive. The loss of endocytosis after alkaline phosphatase treatment of lysosomal enzymes supports the hypothesis that the phosphorylated sugars compete with a phosphorylated carbohydrate on the enzymes for binding to the cell-surface receptors [Kaplan, Achord & Sly (1977) Proc. Natl. Acad. Sci. U.S.A.74, 2026-2030]. Endocytosis of ;low-uptake' forms of alpha-N-acetylglucosaminidase and alpha-mannosidase was likewise susceptible to inhibition by sugar phosphates and by alkaline phosphatase treatment, suggesting that ;low-uptake' forms are either contaminated with ;high-uptake' forms or are internalized via the same route as ;high-uptake' forms. The existence of an alternative route for adsorptive endocytosis of lysosomal enzymes is indicated by the unaffected adsorptive endocytosis of rat liver beta-glucuronidase in the presence of phosphorylated sugars and after treatment with alkaline phosphatase.
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PMID:Evidence for lysosomal enzyme recognition by human fibroblasts via a phosphorylated carbohydrate moiety. 64 6


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