Automated colorimetric determination of acid proteinase activity in fermentation samples using a trinitrobenzenesulphonic acid reagent

Abstract

An automated method for the determination of acid proteinase activity has been developed. The enzyme is incubated with a haemoglobin substrate after which the reaction solution is dialysed. The concentration of the liberated amino acids and peptides is determined by reaction with a trinitrobenzenesulphonic acid reagent. The technical parameters of the process and the general analytical conditions have been optimised. The method offers great advantages in its flexibility of selecting substrate and buffer independently of the conditions for the colour reaction. The final result is an automated method with high sensitivity, precision and speed. The sensitivity of the colour reaction is 1 mg 1-1 of nitrogen from leucine.

The effect of environmental conditions on extracellular protease activity in controlled fermentations of Aspergillus niger

“…Extracellular proteolytic activities were measured according to a modified procedure as described by Holm (1980) activity of cleared culture supernatants was determined by incubating 2 or 8 ml samples with 75 ml 0.5 % (w/v) N,N-dimethylated BSA in 0.25 M sodium acetate buffer, pH 4.0, for 17.5 min at 37 uC. As a blank, samples were incubated with sodium acetate buffer without N,N-dimethylated BSA.…”

Spectrophotometric Determination of Amlodipine Besylate in Tablets With Trinitrobenzene Sulphonic Acid : Tabletlerdeki̇ Amlodi̇pi̇n Besi̇lat'in Tri̇ni̇trobenzen Sülfoni̇k Asi̇t İle Spektrofotometri̇k Tayi̇ni̇

“…-0.5 % TNBS solution was prepared by 1/10 dilution of the reagent with water. The reagent is prepared freshly everyday and must be protected against light (15).…”

Potentiometric determination of L‐dopa, carbidopa, methyldopa and aspartame using a new trinitrobenzenesulfonate selective electrode

“…The standard addition method [I81 was used, in which small increments of 0.1 M TNBS-solution were added to 50 mL samples of various concentrations at the appropriate pH value (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The change in emf was recorded after each addition and used to calculate the concentration of the TNBS-sample solution.…”