Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P00790 (PGA)
 2,475 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the course of our studies on the putative role of pectins in the control of cell growth, we have investigated the effect of cadmium on their composition, remodelling and distribution within the epidermis and fibre tissues of flax hypocotyl (Linum usitatissimum L.). Cadmium-stressed seedlings showed a significant inhibition of growth whereas the hypocotyl volume did not significantly change, due to the swelling of most tissues. The structural alterations consisted of significant increase of the thickness of all cell walls and the marked collapse of the sub-epidermal layer. The pectic epitopes recognized by the anti-PGA/RGI and JIM5 antibodies increased in the outer parts of the epidermis (external tangential wall and junctions) and fibres (primary wall and junctions). Concomitantly, there was a remarkable decrease of JIM7 antibody labelling and consequently an increase of the ratio JIM5/JIM7. Conversely, the ratio JIM7/JIM5 increased in the wall domains closest to the plasmalemma, which would expel the cadmium ions from the cytoplasm. The hydrolysis of cell walls revealed a cadmium-induced increase of uronic acid in the pectic matrix. Sequential extractions showed a remodelling of both homogalacturonan and rhamnogalacturonan I. In fractions enriched in primary walls, the main part of the pectins became cross-linked and could be extracted only with alkali. In fractions enriched in secondary walls, the homogalacturonan moieties were found more abundantly in the calcium-chelator extract while the rhamnogacturonan level increased in the boiling water extract.
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PMID:Cadmium-induced alterations of the structural features of pectins in flax hypocotyl. 1708 99

An edible biopolymer poly(gamma-glutamic acid) (gamma-PGA) was evaluated for possible use as an chelating/binding agent in the treatment of metal intoxication in humans. In vitro binding of the toxic heavy metals lead and cadmium as affected by pH, contact time, metal concentration, gamma-PGA dose, and essential metals was carried out in a batch mode. A maximum binding occurred in the pH range 5-7, corresponding to the gastrointestinal pH values except for the stomach. Binding isotherms at pH 5.5 were well described by the heterogeneous models (Freundlich and Toth), while the lead isotherm at pH 2.5 showed a S-type curve, which was fitted as multiple curves with the Langmuir model and a shifted-squared Langmuir model. However, no adsorption occurred for cadmium at pH 2.5. The maximum binding capacities of lead and cadmium at pH 5.5 were 213.58 and 41.85 mg/g, respectively. A curvilinear biphasic Scatchard plot signified a multisite interaction of metals. Binding was extremely rapid with 70-100% of total adsorption being attained in 2 min. Kinetics at low and high metal concentrations obeyed pseudo-first-order and pseudo-second-order models, respectively. The gamma-PGA dose-activity relationship revealed a low dose of gamma-PGA to be more efficient in binding a large amount of metals. Incorporation of Cu, Zn, Fe, Mg, Ca, and K showed only a minor influence on lead binding but significantly reduced the binding of cadmium.
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PMID:In vitro binding of heavy metals by an edible biopolymer poly(gamma-glutamic acid). 1912 12

6-Phosphogluconate dehydrogenase (6-PGD, E.C.: 1.1.1.44) was purified and characterized from the hepatopancreas of grass carp (Ctenopharyngodon idella) for the first time. Grass carp represents the second largest aquaculture industry in the world after silver carp, constituting 14.7% of the world aquaculture production, with an average annual increase of 14% in China, mainly as a source of food. The purification procedure involved a single 2', 5'-ADP-Sepharose 4B affinity chromatographic step by using different elution buffers. The enzyme was purified 309-fold with a specific activity of 5.259 U/mg protein and yield of 68%. The purity and subunit molecular weights of the 6-PGD were checked on SDS-PAGE and purified enzyme showed a single band on the gel. The subunit molecular mass was 57 kDa, with an optimum pH, temperature and ionic strength at 7.96, 50 degrees C and 100 mM Tris-HCl, respectively. The Km values of 6-PGA and NADP+ were 0.019 and 0.0052 mM, respectively, while Vm of 6-PGA and NADP+ was 0.69 U/ml. Dissociation constants (Ki) for 6-PGA and NADP+ were 2.05 and 0.12 mM, respectively. NADPH inhibited the enzyme in a competitive manner and its Ki value was 0.032 mM. The Cu2+, Zn2+, Cd2+ and Al3+ showed inhibitory effects on the enzyme with IC50 values of 0.293, 0.099, 0.045 and 1.526 mM, respectively. All tested metals inhibited the enzyme in a competitive manner, indicating that these metals might be toxic even at low concentrations for the 6-PGD. As the fish is one of valuable foodstuff of animal sources for human consumption, under certain environmental conditions, metal ions accumulated in fish up to a lethal concentration may be harmful for human health. Therefore, it is impending to reduce the concentration of metal ions in contaminated lakes and rivers for fishery and also for human health.
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PMID:Purification and characterization of 6-phosphogluconate dehydrogenase (6-PGD) from grass carp (Ctenopharyngodon idella) hepatopancreas. 2477 81