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Purification and characterization of a highly thermostable glucose isomerase produced by the extremely thermophilic eubacterium, Thermotoga maritima
Author(s) -
Brown Stephen H.,
Sjøholm Carsten,
Kelly Robert M.
Publication year - 1993
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260410907
Subject(s) - thermotoga maritima , thermostability , thermophile , xylose isomerase , glucose 6 phosphate isomerase , biochemistry , isomerase , xylose , enzyme , histidine , chemistry , biology , fermentation , escherichia coli , gene
Thermotoga maritima , among the most thermophilic eubacteria currently known, produces glucose isomerase when grow in the presence of xylose. The purified enzyme is a homotetramer with submit molecular Wight of about 45,000. It has a number of features in common with previously described glucose isomerases‐pH optimum of 6.5 to 7.5, presence of activesite histidine, requirement for metal cations such as Co 2+ and Mg 2+ , and preference for xylose as substrate. In addition, it has significant sequence/structural homology with other glucose isomerases, as shown by both N‐terminal sequencing and immunological crossreactivity. The T. maritima enzyme is distinguished by its extreme thermostability–a temperature optimum of 105 to 110°C, and an estimated half‐life of 10 minutes at 120°C, pH 7.0. The high degree of thermostability, coupled with a neutral to slightly acid pH optimum, reveal this enzyme to be a promising candidate for improvement of the industrial glucose isomerization process © 1993 Wiley & Sons, Inc.