Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00080 (Leaf)
 21,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The transport and phosphorylation of 2-deoxy-D-[3H]galactose in rabbit renal cortical cells was studied. 1. The uptake of 2-deoxy-galactose by cortical slices is associated with an appearance of both free and phosphorylated sugar in the cells. At 1 mM external sugar the cells establish a steady-state gradient of free 2-deoxy-galactose of 3.97 +/- 0.15 (23 animals). 2. The acid-labile sugar phosphate accumulated in the tissue has been identified by a combination of paper and radio-chromatography, as well as on the basis of some of its chemical properties, as 2-deoxy-D-galactose 1-phosphate. Ice-cold trichloroacetic acid produces a decomposition of this compound. 3. Increasing external pH (6-8) brings about a decrease in the steady-state levels of both free and phosphorylated sugar in slices. On the other hand, increasing pH activates the phosphorylation of 2-deoxy-D-galactose by a crude kinase in a tissue extract. 4. Sugar phosphate accumulated in the cells is dephosphorylated by the action of a Zn2+ -activated phosphatase. 5. The efflux of 2-deoxy-D-galactose from the cells is rather slow compared with that found for D-galactose. The efflux is associated with some dephosphorylation of cellular sugar phosphate, and some loss of 2-deoxy-galactose phosphate into the wash-out medium takes place. 6. An inhibition analysis of the uptake of 2-deoxy-D-galactose by the slices indicates that the transport site is shared by D-galactose. The following points of interaction between the sugar molecule and the carrier are identified: C1-OH, C3-OH and C4-OH (both axial) and C6-OH. A (pyranose) ring structure is also essential. A close packing between the substrate and the carrier in the vicinity of C2 is indicated. 7. The data suggest that the above transport system is localized predominantly at the antiluminal (basolateral) face of the renal tubular cells. While the detailed mechanism of the actual transport step (i.e. active transport of the free sugar, or by the action of a phosphotransferase) is still unclear, the data present evidence that both galactokinase and a Zn2+ -activated phosphatase participate in the maintenance of an intracellular steady state of the transported sugar.
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PMID:Transport and phosphorylation of 2-deoxy-D-galactase in renal cortical cells. 1 Sep 99

A levansucrase was demonstrated in the growth medium and in association with the cell surface of Actinomyces viscosus. The amount of enzyme produced relative to cell density is not significantly affected by the growth conditions. Sugar alcohols inhibit growth of the cells. The levansucrase hydrolyzes sucrose to produce free glucose and levan; some free fructose is also formed. There is no requirement for cofactors. The Km for sucrose is 12 mM. A variety of heavy metal ions and two disaccharides, lactose and cellobiose, inhibit the enzyme. The levansucrase was purified to homogeneity and has a specific activity of 90 micronmol of glucose release per min per mg. The enzyme has a molecular weight of 220,000 and is composed of subunits of molecular weight 80,000. The levan product contains both beta(2 leads to 1) and beta(2 leads to 6) linkages. The enzyme remains tightly bound to the levan product, resulting in the formation of high-molecular-weight polymer on the order of 10(8) daltons. The possible role of the levan and levansucrase of A. viscosus in the pathogenesis of periodontal disease is discussed.
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PMID:Levan and levansucrase of Actinomyces viscosus. 1 93

1. pH-dependence of glycolysis has generally been ascribed to the effects of pH on the activities of glycolytic enzymes. The present study shows that sugar transport is pH-dependent in cultured Ehrlich ascites-tumour cells. 2. The rates of glucose consumption, of 3-O-methylglucose transport, and of 2-deoxyglucose transport and phosphorylation increased as linear functions of pH, as the pH of the cell culture medium was increased from 6.1 to 8.5. Transport of glucose, as measured in ATP-depleted cells, was pH-dependent to the same extent as transport of the non-metabolizable sugars. 3. Glucose consumption rates were about 8-fold higher at pH 8.5 than at pH 6.4. About 65-85% of glucose was converted into lactate. Sugar transport rates were 2.5-fold higher at pH 8.5 than at pH 6.3. 4. pH affected both simple diffusion and facilitated diffusion. pH effect was mainly on the Vmax. of 2-deoxyglucose uptake, and on the rapid-uptake phase of 3-O-methylglucose transport. 5. It was estimated that about 70% of the pH effect on the rates of glucose consumption may be due to the effect on sugar transport and the remainder to the effect on the activities of glycolytic enzymes.
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PMID:The pH-dependence of sugar-transport and glycolysis in cultured Ehrlich ascites-tumour cells. 3 Apr 54

Bioflavonoids are potent inhibitors of lactate transport in Ehrlich ascites tumor cells. The most effective bioflavonoids have four to five hydroxyl groups. Sugar substitution at carbon three, or reduction of the double bond between carbons two and three, decreases their inhibitory activity. Quercetin, the most extensively studied of these compounds, inhibits lactate efflux by 50% at 0.1 micrograms/mg of protein. On addition of quercetin to glycolyzing Ehrlich ascites tumor cells, lactate accumulates inside the cell and the intracellular pH drops. Total lactate production is also inhibited. Nigericin prevents the internal acidification that occurs in the presence of quercetin and also reduces the inhibition of glycolysis. Thus, it appears that inhibition of lactate efflux can affect glycolysis through a lowering of the intracellular pH. The inhibitory effect of quercetin on glycolysis can be explained by its effect on lactate efflux and its previously reported effect on the Na+--K+ ATPase [Suolinna, E.--M., et al. (1974) J. Natl. Cancer Inst. 53, 1515].
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PMID:Inhibition of lactate transport and glycolysis in Ehrlich ascites tumor cells by bioflavonoids. 3 32

Antigenic analyses of Lactobacillus fermenti were carried out by double immunodiffusion in agar using extracts prepared with cold trichloroacetic acid (TCA) or hot dilute hydrochloric acid (HCL). A common antigen of L. fermenti, designated as antigen f by the author, was extracted from whole cells with dilute HCL, but not with TCA. The antigen f was also observed in Lactobacillus casei. In addition, all strains isolated from human saliva contained antigen 6 in their cell walls, while the antigen was not observed in most of the isolates from human feces. Therefore, L. fermenti could be divided into two subgroups based upon the existence of antigen 6. Antigen 7 which was demonstrated in some strains of L. fementi was shared by other species of lactobacilli belonging to the serological groups D and E. The common antigen 3 found in lactobacilli was extracted from all strains of L. fermenti Sugar components of cell walls were mainly galactose, glucose and glucosamine (including N-acetylglucosamine), but a small amount of rhamnose was present in the cell wall of only one strain. Inhibition tests with various sugars showed that the serologically active sugars were galactose for antigen f and glucose for antigen 6.
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PMID:Antigenic analyses of Lactobacillus fermenti. 5 Apr 68

Antigens specific for Lactobacillus acidophilus were investigated by double immunodiffusion in agar-gel. Antigenic materials were extracted from whole bacteria and some walls with cold trichloroacetic acid. Antisera were prepared by intravenous injection into rabbits of suspensions of whole organisms in solutions of bovine serum albumin, which had been heated and then washed. Four specific antigens were found as precipitinogens and denoted as antigens 11, 12, 13 and 14. Of 43 strains of L. acidophilus studied, 33 strains possessed antigen 11, six strains antigen 12, two strains antigen 13 and two strains antigen 14. Sugar compositions of wall preparations were analysed in an attempt to characterize the determinants of antigens 11 and 12. The walls contained glucose, galactose, hexosamine and sometimes glycerol, but no rhamnose was found. It was considered that alpha-glucopyranose was the major component of the determinant of antigen 11 since trehalose and maltose significantly inhibited the reaction between antibody 11 and its antigen; the determinant of antigen 12 was not clarified.
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PMID:Specific antigens of Lactobacillus acidophilus. 7 99

Investigation into the vascularization of the Ganglion spirale of the rat showed an irregular, loose network of capillaries, with a somewhat denser vacularization of the marginal areas of the ganglion; the horseradish peroxidase benzidine test according to Sugar was used to demonstrate the vessels. At least of the blood supply of the ganglion is effected via the vessels which run parallel to the nerve fibres through the osseous canals from the modiolus into the Rosenthal canal. The density of vascularization of the Ganglion spirale is surprisingly small, namely 1.89% by volume. The comparative figure for the Ganglion spirale, also measured by means of stereological methods, is approximately 6.8% by volume, whilst the vessels in the Nervus cochlearis occupy 2.1% by volume. The vascularization density of the ganglion corresponds roughly to that of the Cortex cerebri. Electro-microscopical tests have shown that there are unfenestrated capillaries with a small number of pinocytotic vesicles. Possible conclusions as to the permeability of the capillaries are discussed in the paper. The blood supply of the Ganglion spirale has so far received only little attention. In the case of internal ear diseases of vascular genesis, attention is mainly given to changes in the vessels of the lateral wall of the cochlea. Experimental findings, however, show the high sensitivity of the nervous apparatus of the cochlea in the case of disturbed blood supply.
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PMID:[Vascularization of the ganglion spirale cochleae of the rat (author's transl)]. 7 71

We have shown [Mesa-Tejada, R., Keydar, I., Ramanarayanan, M., Ohno, T., Fenoglio, C. & Spiegelman, S. (1978) Proc. Natl. Acad. Sci. USA 75, 1529--1533] that an antigen immunologically related to gp52, a 52,000-dalton glycoprotein of the mouse mammary tumor virus, can be identified in sections of human breast cancer by means of an indirect immunoperoxidase technique. The specificity of the reaction was established by absorption experiments which revealed that only purified gp52, or material containing it, served to eliminate the IgG molecules responsible for the immunohistochemical reaction in the human breast tumors. We show here that the cross-reactivity between the human and murine tumor antigens is due to the polypeptide rather than the polysaccharide components of gp.52. Sugar-free gp52 prepared by deglycosylation with a mixture of glycosidases was as fully effective as the intact gp52 in removing from anti-MMTV the IgG responsible for the reaction with the human tumor antigen. In contrast, the isolated polysaccharide of gp52 was unable to exert blocking activity.
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PMID:Human breast carcinoma antigen is immunologically related to the polypeptide of the group-specific glycoprotein of mouse mammary tumor virus. 8 56

Research on the sugar metabolism of the crystalline lens, past and preent, is reviewed. The chief energy source in the lens is the Embden-Meyerhof pathway; respiration and oxidative phosphorylation become more important as the lens ages. The function of the alpha-glycerophosphate cycle is not fully understood. The mechanisms involved in cataract formation, including those of hypoglycemic cataract and osmotic cataracts, are discussed. Sugar cataracts can be delayed or prevented with such aldose reductase inhibitors as flavonoids. By inhibiting aldose reductase, the formation and accumulation of sugar alcohols is stopped. This approach may be useful as a medical therapy for human diabetic senile cataracts.
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PMID:Sugar metabolism in the crystalline lens. 10 Aug 92

Sugar degradation tests (SDT) were compared with immunofluorescence (IFL) and co-agglutination (COA) tests for the diagnosis of Neisseria gonorrhoeae (GC) and Neisseria meningitidis (MC). Somewhat more than 5% of the GC strains and 8% of the MC strains were misinterpreted by SDT. On most occasions the disagreement between SDT and serological tests was due to the inability of the MC strains (less so for GC strains) to degrade sugars correctly. Because of this, three out of 15 strains (20%) from pharyngeal specimens were primarily considered to be GC by SDT but were identified as MC by COA tests. Deficiencies in sugar degradations were also found in a group of clinical problem strains. Many of them were unable or had a decreased ability to degrade glucose or maltose but were diagnosed distinctly as MC by the COA test. There were no false positives with the IFL or COA tests, but 2% of the GC strains and 26% of the MC carrier strains (non-groupable) were not identified by COA. Both IFL and COA tests are good adjuncts to SDT for the diagnosis of GC and clinically significant MC, since the results are reliable and the tests rapid and simple to perform.
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PMID:Laboratory identification of pathogenic Neisseria with special regard to atypical strains: an evaluation of sugar degradation, immunofluorescence and co-agglutination tests. 10 65


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