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

Stripped human hemoglobin was shown to have a high apparent zinc association constant of 1.3 X 10(7) M-1 with a stoichiometry of one zinc for every two hemes. The saturation of this site produces a dramatic 3.7-fold increase in the oxygen affinity. The effect of zinc on the oxygen affinity is interrelated with the interaction of 2,3-diphosphoglyceric acid (2,3-DPG) and hemoglobin. Thus, a smaller zinc effect is observed in the presence of added 2,3-DPG. Information about the location of the zinc-binding site responsible for the increased oxygen affinity has been obtained by comparing the binding of zinc to various hemoglobins. Blocking the beta93 sulfhydryl group decreases the apparent zinc association constant by an order of magnitude. The substitution of histidine-beta143 in hemoglobin Abruzzo [beta143 (H21) His leads to Arg] and hemoglobin Little Rock [beta143 (H21) His leads to Gln] decreases the apparent zinc association constant by two orders of magnitude. The substitution of histidine-beta143 by other amino acids and the reaction of the beta93 sulfhydryl group are known to produce dramatic increases in the oxygen affinity. The binding of zinc to one or both of these amino acids can, therefore, explain the zinc-induced increase in the oxygen affinity.
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PMID:Interaction of zinc and hemoglobin: binding of zinc and the oxygen affinity. 2 Sep 32

The activity of a pyrophosphate-splitting tissue factor in jaws, teeth and intestinal mucosa has been studied by means of histochemistry. Freeze-cut, unfixed sections of whole animals were incubated in a buffered medium (pH 8.6) containing inorganic pyrophosphate (PP) Pb2+, Mg2+, and Zn2+ at various concentrations. The effects of compound R 8231, heat, aldehyde fixation, and demineralization with EDTA were also investigated. In sections showing optimal staining, deposition of incubation products was found in the stratum intermedium and the subodontoblastic cells of the developing tooth, in the osteoblastic layers, and at the surface of the intestinal mucosa. The hard tissues were also stained except in the demineralized sections. Treatment with heat or compound R 8231 resulted in loss of originally observed soft tissue staining while short-time demineralization with EDTA enhanced the staining reaction. It is argued that a nonspecific deposition of the capturing ion, Pb2+, can hardly explain the observed soft tissue staining. The results point to the presence of a PP-splitting enzyme, and it is suggested that the enzyme exhibits features of an alkaline phosphatase with PP-phospholhydrolytic properties rather than of an inorganic pyrophosphatase.
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PMID:Histochemical localization of alkaline pyrophosphate- phosphohydrolase in tooth-forming cells of rat. 17 19

1. UDP-glucose-sterol glucosyltransferase and nucleoside diphosphatases were isolated in a particulate fraction from 7-day-old etiolated pea seedlings. The glucosyltransferase and UDPase (uridine diphosphatase) are stimulated by Ca2+ cation, less so by Mg2+ cation, and inhibited by Zn2+. 2. Each activity has a pH optimum near 8. 3. The glucosyltransferase is specific for UDP-glucose as the glucosyl donor and is inhibited by UDP. Partial recovery from UDP inhibition is effected by preincubation of the enzyme. 4. Freeze-thaw treatment and subsequent sucrose-density-gradient centrifugation of the particulate fraction shows the glucosyltransferase to be widely distributed among cell fractions but to be most active in particles with a density of 1.15 g/ml. UDPase is most active in particulate material with a density of over 1.18 g/ml but an activity peak also appears at 1.15 g/ml. Of several nucleoside diphosphatase activities, UDPase activity is most enhanced by the freeze-thaw and sucrose-density-gradient-fractionation procedures. 5. Detergent treatment with 0.1% sodium deoxycholate allows the partial solubilization of the glucosyltransferase and UDPase. The two activities are similarly distributed between pellet and supernatant after high-speed centrifugation for two different time intervals. 6. A role for UDPase in the functioning of glucosylation reactions is discussed.
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PMID:Uridine diphosphate glucose-sterol glucosyltransferase and nucleoside diphosphatase activities in etiolated pea seedlings. 20 95

Serum levels of copper and zinc were measured in 111 healthy women in whom Latex Leaf IUDs containing copper and zinc had been inserted. The women ranged from 21 to 41 years of age. Months of use ranged from 1 to 23 with an average of 14.6. The 1st blood sample was obtained before insertion and the 2nd from 1 to 19 months after insertion. Mean level of serum copper in the 1st sample was 1.42 mcg/ml. Age and parity had no effect; a slight tendency for higher levels was observed only in multigravidas. There were no significant changes in mean copper levels even when the levels were correlated with duration of usage. Mean serum zinc level before insertion was 1.1 mcg/ml with no correlation to age, gravidity, or parity. The 2nd sample showed a slight increase, 109% + or -3.25% standard error p .005. This increase correlated with the time the device was in situ. In general, patients with low levels of serum copper or zinc before insertion usually had increased levels after use but these levels did not exceed the upper limits of normal values. This may be due to an initially low level of the copper fraction bound to serum albumin and indicates the existence of some equilibrium between free and bound metal in the system.
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PMID:The effect of intrauterine devices containing zinc and copper on their levels in serum. 62 Aug 40

1. The subcellular location of superoxide dismutase in the leaves of spinach and other C3 plants has been investigated. 2. Most activity appeared to be located within chloroplasts. These organelles contain a cyanide-sensitive (copper-zinc) superoxide dismutase, most of which is located in the stroma although some is bound to the thylakoids. 3. Intact chloroplast fractions also contain a cyanide-insensitive (manganese) superoxide dismutase, but this activity is located on the outside of the chloroplasts and may be adsorbed onto them during isolation. 4. Leaf mitochondrial fractions contain only a small percentage of total leaf superoxide dismutase activity, but there is more than can be accounted for by contamination with chloroplasts. 5. Mitochondria contain both a cyanide-sensitive dismutase, apparently located in the intermembrane space, and a cyanide-insensitive activity, apparently located in the matrix. 6. The microsomal fraction contains no superoxide dismutase activity.
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PMID:Subcellular localisation and identification of superoxide dismutase in the leaves of higher plants. 72 73

Since agricultural crops contribute > 70% of human cadmium (Cd) intake, modification of crops to reduce accumulation of this pollutant metal during plant growth is desirable. Here we describe Cd accumulation characteristics of seedlings and field grown tobacco plants expressing the Cd-chelating protein, mouse metallothionein I. The objective of the transformation is to entrap Cd in roots as Cd-metallothionein and thereby reduce its accumulation in the shoot. Transformed and control seedlings were exposed for 15 days in liquid culture at a field soil-solution-like Cd concentration of 0.02 microM. Transformed seedlings of Nicotiana tabacum cultivar KY 14 contained about 24% lower Cd concentration in shoots and about 5% higher Cd concentration in roots than control seedlings. Dry weights of transformed and control tissues did not differ significantly. In the field in 1990, mature transformed N. tabacum cv. KY 14 plants exposed only to endogenous soil Cd contained about 14% lower leaf lamina Cd concentration than did controls. Differences were significant at the p < or = 0.1 level in 13 of 16 leaf positions. Leaf dry weight did not differ significantly but transformed field plants had 12% fewer leaves and were 9% shorter than the controls. Copper (Cu) concentration was significantly higher (ca10%) in the bottom nine leaf positions of transformed plants suggesting that reduced leaf number and plant height may be due to Cu deficiency or toxicity. Alternatively, somaclonal variation or gene position effects may be involved. No differences were found in zinc levels. With N. tabacum cv. Petit Havana, transformed seedlings contained no less Cd in shoots but 48% higher Cd concentration in roots.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Tissue partitioning of cadmium in transgenic tobacco seedlings and field grown plants expressing the mouse metallothionein I gene. 130 Dec 16

Market baskets containing sixty food items included in the average Swedish diet were purchased from three shops in four major Swedish cities during autumn 1987. Food items were selected on the basis of food-balance-sheet data. Freeze-dried homogenates representative of each city were analysed for twelve essential or toxic mineral elements. The energy content of the market baskets (11.5 MJ) corresponded to the reference value for male adults. At this energy level the contents of calcium (1180 mg), magnesium (300 mg), iron (16 mg), zinc (12 mg) and selenium (44 micrograms) were above or close to the Swedish recommended daily intakes. The contents of manganese (3.7 mg) and molybdenum (150 micrograms) were within and that of copper (1.2 mg) was below the safe and adequate intake values given in the US recommended dietary allowance (Food and Nutrition Board, National Research Council, 1989). The content of nickel was 82 micrograms. The contents of lead (17 micrograms), cadmium (12 micrograms) and mercury (1.8 micrograms) in the daily diet were low compared with the provisional tolerable intakes set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (World Health Organization, 1972, 1989). The market-basket contents of Ca, Mg, Fe and Zn calculated from values in the Swedish food composition tables were close to the analysed values, indicating that the Swedish food tables provide relevant information for the estimation of the dietary supply of these elements.
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PMID:Contents of essential and toxic mineral elements in Swedish market-basket diets in 1987. 176 Apr 40

Sixteen welders, welding under typical New Zealand conditions, had ambient air within their welding helmets sampled and analysed for ozone, nitrogen oxides, fluoride, carbon monoxide, aluminium, chromium, iron, nickel, zinc and total dust. Postshift urinary metals were also analysed, and a respiratory questionnaire completed for each welder. Levels above the New Zealand Workplace Exposure Standard (WES) were found for nitrogen dioxide in four welders (two TIG, one MMA and one plasma cutter), and for total chromium in one plasma cutter, who also had a nickel level of 24% of the WES. Dust levels were highest in the plasma cutters, with one reaching 8.67 mg/m3 (WES = 5 mg/m3). Urinary levels however did not indicate excessive short or long term uptake. Where efficient fume extraction was in use, levels of air contaminants were lower than with natural ventilation. Respiratory symptoms were reported by 67% of welders, 38% meeting criteria for chronic bronchitis (relative risk = 2.0). Smoking welders reported more symptoms than nonsmoking welders.
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PMID:Exposure to fumes in typical New Zealand welding operations. 189 Nov 37

Plasma zinc, iron, copper, and selenium and selected blood proteins were measured in 66 men before (BHW) and after (AHW) a 5-d period of sustained physical and psychological stress called Hell Week. Recovery blood samples were obtained from 26 men 7 d after Hell Week. Dietary intakes were determined BHW and during Hell Week; zinc, iron, copper, and selenium intakes during Hell Week averaged 23.6 +/- 3.4 mg/d, 35.4 +/- 3.9 mg/d, 3.0 +/- 0.5 mg/d, and 92.5 +/- 26.7 micrograms/d, respectively. C-reactive protein was detected in only five subjects BHW and in all subjects AHW. Zinc, iron, selenium, and albumin decreased by 33%, 44%, 12%, and 9%, respectively, whereas ferritin, ceruloplasmin, and creatine kinase concentrations increased AHW by 59%, 8%, and 266%, respectively. Haptoglobin concentrations increased 57% in 30 subjects but decreased 32% in 23 subjects AHW. The biochemical changes were transitory because protein (except ferritin) and mineral concentrations were similar to BHW values 7 d after Hell Week. Hell Week induced changes characteristic of an acute-phase response in physically active men.
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PMID:Biochemical indices of selected trace minerals in men: effect of stress. 198 37


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