Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0220723 (PCA)
 4,687 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method for a simultaneous separation of malondialdehyde (MDA), ascorbic acid and adenine nucleotide derivatives in biological samples by ion-pairing high-performance liquid chromatography is presented. The separation is obtained by an LC-18-T 15 cm x 4.6 mm 3 microns particle size column using tetrabutylammonium as the pairing ion. The starting buffer consists of 10 mM tetrabutylammonium hydroxide, 10 mM KH2PO4 plus 1% methanol, pH 7.00. A step gradient is formed using a second buffer consisting of 2.8 mM tetrabutylammonium hydroxide, 100 mM KH2PO4 plus 30% methanol, pH 5.5. Under these chromatographic conditions a highly resolved separation of MDA, ATP, ADP, AMP, adenosine, ascorbic acid, GTP, GDP, IMP, inosine, Hypoxanthine, Xanthine, uric acid, NAD, and NADP can be performed in about 36 min. In addition, the separation of NADH and NADPH can also be obtained; this renders the present method suitable for the detection of these reduced coenzymes in alkaline extracts from tissue samples. Data referring to PCA extracts from ischemic and reperfused isolated rat hearts and from human erythrocytes peroxidized in vitro by a challenge with 1 mM NaN3 and various concentrations of H2O2 are reported. The relevance of this chromatographic method lies in the possibility to determine directly MDA concentrations avoiding the unspecific thiobarbituric acid colorimetric test, any other manipulation of the sample out of the PCA extraction, and any possible coelution of other acid soluble compounds. The simultaneous determination of MDA, ascorbic acid, and of ATP and its degradation products gives the opportunity to correlate, by a single chromatographic run, peroxidative damages with the energy state of the cell which is of great importance in studies of ischemic and reperfused tissues.
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PMID:Simultaneous separation of malondialdehyde, ascorbic acid, and adenine nucleotide derivatives from biological samples by ion-pairing high-performance liquid chromatography. 195 65

The glutamate dehydrogenase catalyzed reduction of delta 1-pyrroline-2-carboxylic acid (PCA; an alpha-imino acid) with reduced nicotinamide adenine dinucleotide phosphate (NADPH) to give L-proline and NADP+ is employed as a model for the redox step of the corresponding enzyme-catalyzed reductive amination of alpha-ketoglutarate. We demonstrate the reversibility of the model reaction and measure its equilibrium constant. The pH profiles for the model reactions show that the active substrates are the N-protonated imino acid in one direction and the proline anion with a neutral amino group in the other. The V/K value for the imino acid reduction is enhanced by a group Z of pK = 8.6 in the enzyme-NADPH complex, while that for the proline reaction is unaffected by any such group in the enzyme-NADP+ complex. The following conclusions emerge from a comparison of the pH dependence of the rates for the model reactions with that for the oxidative deamination of L-glutamate [Rife, J. E., & Cleland, W. W. (1980) Biochemistry 19, 2328]. The N-protonated form of alpha-iminoglutarate and the conjugate base of glutamate are the active substrates. The redox step is not sensitive to the protonation state of the groups that catalyze the hydrolysis of bound alpha-iminoglutarate. The group Z, which facilitates the PCA reaction, plays no role in the binding of alpha-ketoglutarate. We propose a chemical mechanism for the glutamate reaction where an unprotonated enzyme group of pK = 5.2 in enzyme-NADPH catalyzes the conversion of the alpha-iminoglutarate to the carbinolamine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reversible reduction of an alpha-imino acid to an alpha-amino acid catalyzed by glutamate dehydrogenase: effect of ionizable functional groups. 399 79

Geobacter sulfurreducens strain PCA oxidized acetate to CO2 via citric acid cycle reactions during growth with acetate plus fumarate in pure culture, and with acetate plus nitrate in coculture with Wolinella succinogenes. Acetate was activated by succinyl-CoA:acetate CoA-transferase and also via acetate kinase plus phosphotransacetylase. Citrate was formed by citrate synthase. Soluble isocitrate and malate dehydrogenases NADP+ and NAD+, respectively. Oxidation of 2-oxoglutarate was measured as benzyl viologen reduction and strictly CoA-dependent; a low activity was also observed with NADP+. Succinate dehydrogenase and fumarate ductase both were membrane-bound. Succinate oxidation was coupled to NADP+ reduction whereas fumarate reduction was coupled to NADPH and NADH Coupling of succinate oxidation to NADP+ or cytochrome(s) reduction required an ATP-dependent reversed electron transport. Net ATP synthesis proceeded exclusively through electron transport phosphorylation. During fumarate reduction, both NADPH and NADH delivered reducing equivalents into the electron transport chain, which contained a menaquinone. Overall, acetate oxidation with fumarate proceeded through an open loop of citric acid cycle reactions, excluding succinate dehydrogenase, with fumarate reductase as the key reaction for electron delivery, whereas acetate oxidation in the syntrophic coculture required the complete citric acid cycle.
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PMID:Oxidation of acetate through reactions of the citric acid cycle by Geobacter sulfurreducens in pure culture and in syntrophic coculture. 1113 Oct 21

Palifermin, a recombinant human keratinocyte growth factor, is commonly given to prevent mucositis following autologous transplantation. In the allogeneic hematopoietic stem cell transplant (allo-HSCT) setting, safety and efficacy data are limited. We conducted a retrospective study in 251 patients undergoing allo-HSCT, 154 of whom received peritransplant palifermin. In all patients, palifermin significantly decreased the mean number of days of total parenteral nutrition (TPN, 13 vs 16 days, P=0.006) and patient-controlled analgesia (PCA, 6 vs 10 days, P=0.023), as well as the length of initial hospital stay (LOS, 32 vs 37 days, P=0.014). However, the effect of palifermin was only significant in patients who received a TBI- but not BU-based chemotherapy conditioning regimen. In TBI recipients, palifermin decreased the mean number of days of TPN (13 vs 17 days, P<0.001) and PCA (7 vs 12 days, P=0.033), and the length of stay (32 vs 38 days, P=0.001). Palifermin did not affect GVHD, graft failure or relapse. Therefore, in the largest analysis with this patient population to date, we demonstrate that palifermin is safe in allo-HSCT patients, decreases TPN and PCA use and decreases LOS following TBI-based but not chemotherapy-based allo-HSCT.
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PMID:Palifermin is efficacious in recipients of TBI-based but not chemotherapy-based allogeneic hematopoietic stem cell transplants. 2275 Sep 97