Ak. Williams et Jt. Hupp, SOL-GEL-ENCAPSULATED ALCOHOL-DEHYDROGENASE AS A VERSATILE, ENVIRONMENTALLY STABILIZED SENSOR FOR ALCOHOLS AND ALDEHYDES, Journal of the American Chemical Society, 120(18), 1998, pp. 4366-4371
Silicate-encapsulated yeast alcohol dehydrogenase (ADH) can be employe
d as a sensor for short-chained alcohols in standard aqueous, harsh no
naqueous, and gas-phase environments. Specifically, the implementation
of sensing schemes based on encapsulated ADH/NAD(+) or ADH/NADH, and
utilization of changes in fluorescence from the soluble, reduced cofac
tor nicotinamide adenine dinucleotide (NADH) upon exposure to alcohols
or aldehydes, allows for semiquantitative determination of both subst
rates. Additionally, by using fluorescence from NADH, we find that cyc
ling of the enzymatic probe can be accomplished via successive exposur
e to alcohol and aldehyde substrates, thus converting the system into
a multiple-use sensor. Finally, we find that the gel matrix provides s
ufficient enzyme stabilization to permit the assemblies to be used ana
lytically in hostile and inherently denaturing sample environments, in
cluding vapor-phase and nonpolar liquid (e.g., hexane) environments.