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Appl. Environ. Microbiol., Apr 1995, 1399-1407, Vol 61, No. 4
K Bronnenmeier, A Kern, W Liebl and WL Staudenbauer
A separation procedure for the analysis of the enzyme components of the
hyperthermophilic bacterium Thermotoga maritima involved in cellulose and
xylan degradation was developed. Resolution of the enzymes was achieved by
a combination of fast protein liquid chromatography anion exchange and
hydrophobic interaction chromatography. Enzyme fractions were assayed for
hydrolysis of Avicel, carboxymethylcellulose (CMC), beta-glucan, laminarin,
xylan, p-nitrophenyl-beta-D-glucoside, p- nitrophenyl-beta-D-cellobioside,
p-nitrophenyl-beta-D-xyloside, p- nitrophenyl-alpha-L-arabinofuranoside,
and 4-O-methyl-glucuronosyl- xylotriose. The activities of two cellulases,
one laminarinase, one xylanase, two putative beta-D-xylosidases,
alpha-D-glucuronidase, and alpha-L-arabinosidase were identified. Because
of their selective retardation on a Superdex gel filtration column, the two
cellulases could be purified to homogeneity. According to sodium dodecyl
sulfate- polyacrylamide gel electrophoresis, molecular masses of 27 and 29
kDa, respectively, were determined for cellulase I and cellulase II.
Maximal activities of both enzymes were observed at 95 degree C between pH
6.0 and 7.5. In the presence of 2.5 M NaC1 the purified enzymes retained
about 90% of their initial activities after a 6-h incubation at 80 degree
C. On the basis of its activity towards CMC, cellulase I was classified as
endo-beta-1,4-glucanase. Cellulase II was able to attack Avicel in addition
to CMC, beta-glucan, and p-nitrophenyl-beta-D- cellobioside. It releases
cellobiose and cellotriose from Avicel. The latter product is further
cleaved into glucose and cellobiose. Cellulase II may therefore be
classified as exo-beta-1,4-glucanase.
Copyright © 1995, American Society for Microbiology
Purification of Thermotoga maritima enzymes for the degradation of cellulosic materials
Institut fur Mikrobiologie, Technische Universitat Munchen, Federal Republic of Germany.
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