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Characteristics of tyrosinase in AOT–isooctane reverse micelles
Author(s) -
Bru Roque,
SanchezFerrer Alvaro,
GarcíaCarmona Francisco
Publication year - 1989
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260340305
Subject(s) - chemistry , substrate (aquarium) , micelle , aqueous solution , tyrosinase , yield (engineering) , ternary operation , nuclear chemistry , chromatography , enzyme , stereochemistry , organic chemistry , materials science , oceanography , computer science , programming language , metallurgy , geology
Isooctane–AOT–H 2 O is a suitable system for studying enzyme behavior in organic solvents. Tyrosinase was able to catalyze a well‐known reaction in aqueous medium: oxidation of 4‐methylcatechol to yield 4‐methyl‐ o ‐benzoquinone. This reaction was studied using the preceding ternary system with adequate amounts of each component to make up reverse micelles. 4‐Methyl‐ o ‐benzoquinone stability was demonstrated in isooctane even at alkaline pH values. Apparent K m and V max were similar to those in water, but substrate inhibition was more evident. The pH and temperature appear to be shifted toward high and low values, respectively. Characteristic parameters of reverse micelles, ω 0 (= H 2 O/AOT) and percentage of H 2 O (v/v), were investigated. The results obtained showed that the steady‐state rate varies either with ω 0 or with percentage of H 2 O. The variation observed with ω 0 showed an optimal value while an increase in percentage of H 2 O can lead to decreased or increased activity depending on substrate concentration.