Author/Authors :
Siah, Maryam Medical Biology Research Center - Kermanshah University of Medical Sciences , Farzaei, Mohammad Hosein Medical Biology Research Center - Kermanshah University of Medical Sciences , Ashrafi Kooshk, Mohammad Reza Medical Biology Research Center - Kermanshah University of Medical Sciences , Adibi, Hadi Pharmaceutical Sciences Research Center - Faculty of Pharmacy - Kermanshah University of Medical Sciences , Khodarahmi, Reza Medical Biology Research Center - Kermanshah University of Medical Sciences
Abstract :
Aldehyde oxidase, a molybdenum cofactor-containing cytosolic enzyme, is
extensively distributed throughout the animal kingdom. The enzyme is mainly
active in liver and other tissues of mammalian species and involved in the
metabolism of wide range of aldehydes and nitrogen-containing molecules. A
continuous spectrophotometric method for the quantitative determination of
aldehyde oxidase, AO, enzyme activity is described in this article. This method
is based on the coupling reaction between 3-methyl-2-benzothiazolinone
hydrazone (MBTH) and the o-quinone. Dopamine as substrate for AO, is
converted/oxidized to o-quinone. The latter react with MBTH to produce
intensely colored products that absorb light maximally in the visible region.
Then, AO activity has been kinetically characterized; the Km (Michaelis–Menten
constant) and Vmax (maximum initial velocity) values for the oxidation of
dopamine by AO were evaluated. The existence of MBTH in the reaction
medium and production of stable color as well as the high ϵ values at 510 nm
of MBTH-Q adduct make this direct technique more sensitive than other
continuous methods for AO assay. The optimized MBTH reaction may be
useful for biological staining of AO activity isolated from various biological
sources in electrophoresis gels.
