Sb. Mcloughlin et Cr. Lowe, AN ENZYMATICALLY ACTIVE ARTIFICIAL REDOX COENZYME BASED ON A SYNTHETIC DYE TEMPLATE, Enzyme and microbial technology, 20(1), 1997, pp. 2-11
An analogue of the reactive textile dye, Cibacron Blue F3G-A, has been
modified with nicotinamide to produce an artificial redox coenzyme, B
lue N-3, whose properties reflect the dual presence of a blue anthraqu
inone chromophore and an N-substituted nicotinamide ring. The reduced
coenzyme generated concomitantly with the oxidation of alcohols by hor
se liver alcohol dehydrogenase (HLADH) displayed difference absorbance
(Delta lambda(max) 333 nm) and H-1-NMR spectra consistent with the pr
esence of a 1,4-dihydro-nicotinamide ring. The artificial coenzyme med
iated the HLADH-catalyzed oxidation of primary aliphatic and cyclic al
cohols with pentan-1-ol being the best cosubstrate of those tested and
exhibiting a turnover of 8.5% of that shown by NAD(+) at pH 9.0 and 2
5 degrees C. The apparent Michaelis constant (K-m for Blue N-3 (38 mu
M) with ethanol as cosubstrate was similar to that of NAD(+) (10 mu M)
determined with HLADH and the reaction followed a similar ordered mec
hanism. The relative catalytic efficiency [k(cat)/K-m(M(-1)s(-1))] of
Blue N-3 was 0.4% of that shown by NAD(+) under these conditions. The
artificial coenzyme also displayed activity with human liver beta(1) b
eta(1) alcohol dehydrogenase and sheep liver sorbitol dehydrogenase, t
wo members of the same long-chain/polyol dehydrogenase family of enzym
es. The artificial coenzyme appears to bind to these enzymes, inducing
a conformational change and producing a catalytically competent compl
ex in a manner similar to the natural coenzyme. (C) 1997 by Elsevier S
cience Inc.