A method for the determination of amylase activity and a useful highly stable color reagent aqueous solution therefore are disclosed. The solution comprises, as a color reagent, an aromatic nitro containing compound such as 3,5-dinitrosalicyic acid, a color stabilizing chelating compound such as ethylenediaminetetraacetic acid, and a hydroxide base. Eliminating the necessity for centrifuging prior to the determination of amylase activity can be achieved by including potassium hydroxide for at least a part of the base in the solution.
A method is disclosed for determining glucose whereby glucose is reacted with an aromatic reagent containing one or more nitro groups and the reaction is monitored at electrodes which measure the current produced by the reduction of one or more of the nitro groups.
A method for the assay of .alpha.-amylase activity, which comprises adding an .alpha.-amylase-containing sample to maltohexaitol or maltohexaonic acid used as substrate, reacting, at the same time or subsequent to the addition, .alpha.-glucosidase with the resulting mixture, and determining the reaction product to assay the .alpha.-amylase activity.
An assay method for amylase activity in a biological specimen such as serum, saliva or urine. The enzyme amylase in the specimen is used to decompose a substrate which is a glucose polymer having a modified reducing terminal glucose residue or a cyclic glucose polymer. A component of the decomposed substrate is measured as an indication of amylase activity in the specimen. The residue may be amylose, amylopectin, starch, starch hydrolyzate, an etherified reducing terminal, an esterified reducing terminal, gluconolactone or a gluconic acid residue or its derivative. Decomposed substrate assay may be effected by contacting the same with maltose dehydrogenase and NAD or NADP, whereupon the assay is performed by measuring the amount of reduced NAD or reduced NADP, by reacting the same with reduced-form hydrogen transport colorimetric reaction reagent. This reagent may be a tetrazolium salt and diaphorase, or tetrazolium salt and phenazinemethosulfate. To remove pre-existing glucose and maltose present in the specimen, the specimen may be pretreated with alpha-glucosidase or kinase in the presence of Mg.sup.++ and ATP, the kinase being for example hexokinase. The preferred maltose dehydrogenase is produced by culturing Bacillus megaterium B-0779 FERM-P No. 5662.
A chromogenic substrate for the assay of polysaccharide endo-hydrolases is the reaction product of a polysaccharide susceptible to endo-hydrolase degradation, a chemical reagent for increasing the solubility of the polysaccharide so as to increase its susceptibility to enzyme degradation, and a dye substance for coloring the polysaccharide and rendering it capable of estimation by absorption spectrometry. The amount of chemical reagent should be such as to produce a degree of chemical substitution in the range 0.06 to 0.6 DS.
Method, kits and reagents for the simultaneous, kinetic spectrophotometric analysis of blood serum samples for multiple components. Pairs of components which may be simultaneously analyzed are: cholesterol and triglyceride; glucose and urea; uric acid and gamma glutamyl transferase; calcium and magnesium; albumins and total protein.
