Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.1.2 (glutamate dehydrogenase)
 4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ammonia has been determined in filtrates of human plasma after precipitation of the proteins by perchloric acid. After restoration of the pH to around 7.5, addition of 2-oxoglutarate, NADH and glutamate dehydrogenase (GDH) convers the ammonia to L-glutamate with oxidation of the NADH to NAD. This latter reaction was utilised in two ways. In the first, reduction of native NADH fluorescence under the conditions of the GDH reaction provided a measure of ammonia concentration. In the second, residual NADH was destroyed by acid treatment, and the fluorescent product generated from NAD under strongly alkaline conditions was assayed. The optimal requirements for both methods were defined, their linearity and precision ascertained, and their relative merits compared. The first method was convenient for "one-off" estimations, and the second for larger batches. Ammonia concentration increased in plasma and in acid protein-free filtrates of plasma irrespective of the conditions of storage; however when the latter were neutralised, storage at -20 degrees C was effective. The distribution of plasma ammonia concentration in healthy subjects was log-normal. The range for males was 21-58 mumol/1 and for females 17-51 mumol/1; this difference was statistically significant (P less than 0.01).
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PMID:The fluorimetric determination of ammonia in protein-free filtrates of human blood plasma. 17 63

Acetylglutamate in HClO4 tissue extracts is first separated from glutamate by ion exchange. It is then deacylated with aminoacylase, and the resulting glutamate, after adsorption to and elution from an AG 50 column, is quantitated by a fast-HPLC method using o-phthaldialdehyde precolumn derivatization, separation in a C18 reverse-phase column, and fluorescence detection. A linear response is obtained up to 2 nmol, the detection limit is 5 pmol, and the method is suitable for assay in 1 mg liver tissue and thus for needle biopsies. When samples were analyzed by this procedure and by earlier procedures based upon detection of glutamate with glutamate dehydrogenase or upon activation of carbamoyl phosphate synthetase the results were similar. The method, which is highly specific, compares favorably in sensitivity, precision, and accuracy with all other published procedures. Using this assay, no acetylglutamate has been found in chicken liver and rat kidney.
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PMID:Determination of N-acetyl-L-glutamate using high-performance liquid chromatography. 399 35

An enzymatic assay was developed for the spectrophotometric determination of glycolate in urine and plasma. Glycolate was first converted to glyoxylate with glycolate oxidase, and the glyoxylate formed was condensed with phenylhydrazine. The glyoxylate phenylhydrazone formed was then oxidized with K(3)Fe(CN)(6) in the presence of excess phenylhydrazine, and A(515) of the resulting 1, 5-diphenylformazan was measured. Since glycolate oxidase also acts on glyoxylate and L-lactate, the incubation of samples with glycolate oxidase was carried out in 120-170 mM Tris-HCl (pH 8.3) to obtain glyoxylate as its adduct with Tris. The pyruvate formed from lactate was removed by subsequent brief incubation with alanine aminotransferase in the presence of L-glutamate, and alpha-ketoglutarate formed was converted back to L-glutamate by glutamate dehydrogenase and an NADPH generating system. Thus the specificity of the assay relies principally on the substrate specificity of glycolate oxidase, and high sensitivity is provided by the high absorbance of 1,5-diphenylformazan at 515-520 nm. Plasma was deproteinized with perchloric acid, and then neutralized with KOH. Plasma and urine samples were then incubated with approximately 5 mM phenylhydrazine, and then treated with stearate-deactivated activated charcoal to remove endogenous keto and aldehyde acids as their phenylhydrazones. The normal plasma glycolate and urinary glycolate/creatinine ratio for adults determined by this method are approximately 8 microM and approximately 0.036, respectively.
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PMID:A spectrophotometric method for the determination of glycolate in urine and plasma with glycolate oxidase. 1073 95