Abstract: .alpha.-Amylase is determined by the enzymatic splitting of an .alpha.-amylase substrate and measurement of a fission product, wherein there is used as a substrate a maltoheptaose compound of the formula ##STR1## wherein R is a glucoside, phenylglucoside, mononitrophenylglucoside, dinitrophenylglucoside, sorbitol or gluconic acid group. Reagents comprising such a substrate and a system for the determination of a fission product formed from the amylase substrate by .alpha.-amylase, are also provided.

Abstract: A method for the quantitative determination of an oxidized pyridine co-enzyme which comprises reacting a sample containing oxidized pyridine co-enzyme in the presence of its specific alcohol dehydrogenase with an aliphatic alcohol of 8 to 16 carbon atoms, oxidizing the aldehyde formed with reduced flavine mononucleotide and oxygen in the presence of luciferase and of the particular FMN-reductase which is independent of the co-enzyme to be determined and of the reduced substrate co-enzyme of the latter, and measuring the resulting light emission as a measure of the initial oxidized pyridine co-enzyme content.

Abstract: Formate, or compounds convertible into formate, is determined by reacting same in the presence of formate dehydrogenase (FDH) and of a hydrogen acceptor, e.g., NAD, wherein the formate dehydrogenase is from Candida boidinii DSM 941, to result in stoichiometric reactions. The process can be used for the removal of formate from solutions containing same.

Abstract: In a process for the determination of substrates or enzyme activities in a test batch, utilizing a conventional redox reaction as a measurement reaction, the improvement comprising carrying out the process in the presence of ascorbate oxidase; the addition of ascorbate oxidase substantially eliminates the interfering effect of ascorbic acid frequently found in the test sample.

Abstract: Ascorbic acid or dehydroascorbic acid is determined by reaction with a tetrazolium salt selected from 3-(4,5-dimethyl-thiazolyl-2)-2,5-diphenyl-tetrazolium bromide, nitrotetrazolium blue, tetrazolium blue chloride and distyryl-nitro blue tetrazolium chloride, in the presence of phenazine methosulphate and a detergent, at a weakly acidic pH value, and evaluating the coloration obtained as a measure of the initial acid content. The method is particularly efficacious in substantially eliminating disturbance of the reaction by foreign substances.