title: An enzymatic method for the alpha-amylase assay which comprises a new procedure for eliminating glucose and maltose in biological fluids.
abstract: An alpha-amylase assay in biological fluids, characterized by a new procedure for eliminating glucose and/or maltose, was developed. The reagent includes thermostable glucokinase, glucosephosphate isomerase and phosphofructokinase obtained from a thermophile Bacillus stearothermophilus. Up to 4,000 mg/dl glucose or 600 mg/dl maltose had no effect on the measured value of alpha-amylase activity when measured at 37 degrees C, even at a serum volume fraction in the reagent of 1/50. Alpha-Amylase activity was monitored by the absorbance increase at 340 nm due to NADPH production. The assay has a high degree of precision, with the within-run and day-to-day coefficients of variation being 2.17% at 75.0 U/l and 2.49% at 112 U/l, respectively, and is linear up to about 2,500 U/l. Regarding interferences, bilirubin, urate, ascorbate, pyruvate, EDTA, sodium fluoride and others were found to have no effect on the assay, and the reagent in solution is stable for about 2 wk at low temperatures (6-8 degrees C).
authors.affiliation: Research and Development Center, UNITIKA Ltd., Kyoto, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kondo
authors.forename: T
authors.initials: T
authors.lastname: Shiraishi
authors.forename: K
authors.initials: K
authors.lastname: Nagata
authors.forename: K
authors.initials: K
authors.lastname: Tomita
mesh_terms: D001826:Body Fluids / Q000201:enzymology*; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D005941:Glucokinase; D005947:Glucose / Q000032:analysis*; D005956:Glucose-6-Phosphate Isomerase; D006801:Humans; D008320:Maltose / Q000032:analysis*; D008722:Methods; D010732:Phosphofructokinase-1; D011933:Reagent Kits, Diagnostic; D000516:alpha-Amylases / Q000032:analysis* / Q000097:blood
chemical_list: D011933:Reagent Kits, Diagnostic; D008320:Maltose; D010732:Phosphofructokinase-1; D005941:Glucokinase; D000516:alpha-Amylases; D005956:Glucose-6-Phosphate Isomerase; D005947:Glucose