Determn. of enzyme substrate or prod. over wide concn. range - by measuring change in absorption properties of enzyme or its complex during reaction, esp. for glucose assay

摘要

Selective determn. of the concn. of dissolved substances (I), which are substrates for or products of enzymatic reactions, comprises measuring the change caused by enzymatic reaction in optical absorption properties of the enzyme (II); the (II)-bound coenzyme (III); the (II)-(III) complex or the (II)-substrate or prod. complex. The concn. of (I) is then determined from the measured change. Device for this process consists of a light source and wavelength-selective detector. Light is passed through a (II)-contg. element and the output signal from the detector is passed to a processing unit for calculation of the (I) concn. Specifically the measured absorbance change is generated by a reduced or oxidised (protonated or deprotonated) intermediate state of (II) or (II)-bound (III). The measurement sensitivity is adjusted by (1) adding an electron (proton) donor or acceptor (A) or (2) electron transfer from an electrode to (II) or vice versa. USE/ADVANTAGE - The method allows (I), esp. glucose, to be determined from extremely low to relatively high concns. (0.1 microM-0.1M) and is not subject to external interference (esp. electromagnetic fields). Applications are in biotechnology, food processing, environmental protection and clinical analysis.