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Appl. Environ. Microbiol., 11 1997, 4355-4359, Vol 63, No. 11
J Lou, KA Dawson and HJ Strobel
Prevotella bryantii is an important amylolytic bacterium in the rumen that
produces considerable amounts of glycogen when it is grown on maltose.
Radiolabel studies indicated that glucose-1-phosphate was converted to
UDP-glucose, and this latter intermediate served as the immediate precursor
for glycogen synthesis. High levels of UDP-glucose pyrophosphorylase
activities (> 1,492 nmol/min/mg of protein) were detected in cells grown
on maltose, cellobiose, glucose, or sucrose, and activity was greatly
stimulated (by approximately 60-fold) by the addition of fructose-1,6-bis
phosphate (half-maximal activation concentration was 240 microM). However,
ADP-glucose pyrophosphorylase activity was not detected in any of the
cultures. Glycogen synthase activity in maltose-grown cultures (48
nmol/min/mg of protein) was higher than that in cellobiose-, sucrose-, and
glucose-grown cultures (< 26 nmol/min/mg of protein). This is the first
report of a bacterium that exclusively uses UDP-glucose to synthesize
glycogen. The elucidation of this unique glycogen biosynthesis pathway
provides information necessary to further investigate the role of bacterial
glycogen accumulation in rumen metabolism.
Copyright © 1997, American Society for Microbiology
Glycogen biosynthesis via UDP-glucose in the ruminal bacterium Prevotella bryantii B1(4)
Department of Animal Sciences, University of Kentucky, Lexington 40546- 0215, USA.
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