C. Arnosti et al., Application of fluorescence spectroscopic techniques and probes to the detection of biopolymer degradation in natural environments, MAR CHEM, 71(3-4), 2000, pp. 321-330
The activities and substrate specificities of extracellular enzymes in natu
ral systems are not well understood, despite their critical role in microbi
al remineralization of organic carbon. These enzymes initiate organic carbo
n degradation by selectively hydrolyzing high molecular weight substrates t
o lower molecular weight products which can be transported into cells. A se
t of single- and dual-labeled fluorescent polysaccharides was synthesized a
nd characterized to explore a variety of approaches for measuring enzymatic
hydrolysis of biopolymers via photophysical techniques, focusing particula
rly on rapid and robust optical techniques which are amenable to field meas
urements in remote locales. A shotgun-labeling approach yielded dual-labele
d probes that exhibited substantial donor fluorophore quenching. The photop
hysical response of these probes to hydrolysis via purified enzymes was inv
estigated in the lab, and fluorescence polarization proved to be a rapid an
d reliable technique for monitoring probe hydrolysis. Initial field results
were also obtained from hydrolysis experiments in sediment porewaters. Bec
ause polarization measurements are rapid and simple, this approach could be
used to follow the extracellular enzymatic hydrolysis of a wide range of b
iopolymers which fuel microbial metabolism. (C) 2000 Elsevier Science B.V.
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