Biomaterial Database

Phosphate determination by enzymatic colorimetric assay. 1985

P Fossati

A direct colorimetric assay for inorganic phosphate in serum is described. The system is based on utilization of the enzymes, purine-nucleoside phosphorylase and xanthine oxidase, to generate superoxide ions. The superoxide is measured in the presence of an electron mediator compound with 3-(4',5'-dimethyl-2-thiazolyl)-2,4-diphenyl-2H-tetrazolium bromide as the chromogen. The high absorbance of this chromogen between 550 and 660 nm affords useful results with a sample/reagent volume ratio as low as 1:100. A single working reagent is used, and the reaction is complete in 15 min at room temperature. The standard curve is linear for inorganic phosphate concentrations as high as 4.9 mmol/liter. Analytical recovery of phosphate in human sera averages 100%. Within-run precision study gives CV less than or equal to 1.0%. The results of this method compare closely (r greater than 0.99) with those obtained by the semidine method (recommended standard). The method lends itself to automation.

UI	MeSH Term	Description	Entries
D010430	Pentosyltransferases	Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D011683	Purine-Nucleoside Phosphorylase	An enzyme that catalyzes the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. EC 2.4.2.1.	Inosine Phosphorylase,Nicotinamide Riboside Phosphorylase,Purine Nucleoside Phosphorylases,Nucleoside Phosphorylases, Purine,Phosphorylase, Inosine,Phosphorylase, Nicotinamide Riboside,Phosphorylase, Purine-Nucleoside,Phosphorylases, Purine Nucleoside,Purine Nucleoside Phosphorylase,Riboside Phosphorylase, Nicotinamide
D003124	Colorimetry	Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D005189	False Positive Reactions	Positive test results in subjects who do not possess the attribute for which the test is conducted. The labeling of healthy persons as diseased when screening in the detection of disease. (Last, A Dictionary of Epidemiology, 2d ed)	False Positive Reaction,Positive Reaction, False,Positive Reactions, False,Reaction, False Positive,Reactions, False Positive
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013053	Spectrophotometry	The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
D014969	Xanthine Oxidase	An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.	Hypoxanthine Oxidase,Hypoxanthine Dehydrogenase,Hypoxanthine-Xanthine Oxidase,Purine-Xanthine Oxidase,Dehydrogenase, Hypoxanthine,Hypoxanthine Xanthine Oxidase,Oxidase, Hypoxanthine,Oxidase, Hypoxanthine-Xanthine,Oxidase, Purine-Xanthine,Oxidase, Xanthine,Purine Xanthine Oxidase