Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.5.2 (NQO1)
 6,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An enzymatic assay method for the determination of urinary formic acid is described. Formic acid in urine was cleaved to carbon dioxide and water by formic acid dehydrogenase, whereby NAD+ was converted to NADH, which reacted with INT (p-iodonitrotetrazolium violet) in the presence of NAD-diaphorase. The color thus produced was determined at 500 nm. In addition, a simple gas chromatographic method of urinary formic acid is described, in which head space gas of formic acid methylester was applied into the wide bore column. The urinary formic acid concentrations by the enzymatic method agreed well with that by the gas chromatographic method. A simple gas chromatographic method for urinary methanol assay is also described. Acetonitrile was added to an equal volume of urine containing methanol. After centrifugation, the supernatant was injected into gas chromatography (GC). The peaks of urinary methanol and ethanol were separated by GC. Formic acid and methanol in urine of unexposed healthy subjects and workers exposed to methanol were analyzed by the colorimetric and gas chromatographic methods. Geometric mean concentrations of urinary formic acid and methanol in the healthy subjects were 7.82 mg/g creatinine and 1.34 mg/l, respectively. The concentration ratio of formic acid to methanol in the urine of the workers exposed to methanol was calculated to be 3.67 +/- 2.10, which agreed with the ratio under a controlled exposure experiment. A slower excretion of formic acid than that of methanol in the urine of a volunteer was also observed.
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PMID:Enzymatic assay of formic acid and gas chromatography of methanol for urinary biological monitoring of exposure to methanol. 234 46

The fluorometric assay for formate in serum was modified by pretreating samples with acetonitrile (1:1) precipitation; substituting p-iodonitrotetrazolium violet (INT) for resazurin; and by combining the cofactor (NAD), coupled enzyme (diaphorase), and secondary substrate (INT) into one reagent. Formate is oxidized by formate dehydrogenase producing NADH which reduces INT via diaphorase to a visible red-colored endpoint that can be measured on a spectrophotometer at 500 nm. Previous problems with fluorometric endpoint methods are eliminated when using this modified procedure: calibration is linear rather than nonlinear; blanking is rarely needed due to the acetonitrile sample preparation; dynamic range is expanded up to 10-fold; a simple spectrometer rather than a fluorometer is used; and the number of steps is reduced. The method is demonstrated to be linear, specific, sensitive, precise, and accurate.
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PMID:Improved enzymic assay for serum formate with colorimetric endpoint. 375 27

An enzymatic method for the determination of plasma formate concentration is described. Formate dehydrogenase is used to reduce NAD+ to NADH in the presence of formate. The resulting NADH then reduces the dye resazurin to resorufin, a reaction catalyzed by the endogenous diaphorase of the plasma. The generated resorufin is then measured fluorimetrically by exciting it at 565 nm and quantitating the emitted light at 590 nm. The method uses the patient's plasma as the blank and as the matrix for the construction of a patient-specific formate calibration curve. The blank contains all components of the assay system except the formate dehydrogenase. Formate concentration is determined from the calibration curve, constructed by adding known quantities of sodium formate to the plasma base, and plotting the fluorescence intensity against formate concentration. The assay which is sensitive to a formate level of 7 mg/L should find application in cases where formate is a metabolite.
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PMID:An enzymatic method for the analysis of formate in human plasma. 654 98