ISSN:
1476-5535
Keywords:
β-Glucosidase
;
C. flavigena
;
Cellobiase
;
Recombinant DNA
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Summary Plasmid-coded β-glucosidase produced byEscherichia coli was characterized and compared to the enzyme produced byCellulomonas flavigena. Cell-free extracts, non-denaturing PAGE and 5-bromo-4-chloro-3-indolyl-β-d-glucopyranoside (X-glu) as substrate were used to compare both enzymes. The β-glucosidase was assayed for cellobiose andp-nitrophenyl-glucopyranoside (PNPG). Cellobiose hydrolysis was performed at 50°C for the enzyme fromC. flavigena and at 37°C for that fromE. coli pJS3, both with an optimal pH of 6.5. For PNPG hydrolysis, the optimal conditions were pH 5.5 and 37°C for both cell extracts. Most of the β-glucosidase activity was intracellular. When cultures ofC. flavigena were grown with cellobiose or carboxymethylcellulose (CMC) as inducers, the expression of β-glucosidase was increased considerably.E. coli pJS3 produces a cellobiase which hydrolyzes cellobiose and PNPG. TheK m values for cellobiose and PNPG indicated that the β-glucosidase activity ofC. flavigena had a higher affinity for cellobiose as substrate, whereas the β-glucosidase fromE. coli pJS3 showed higher affinity for PNPG.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01569764
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