XYLOSE ISOMERASES FROM THERMOTOGALES Authors: B. Fatima, Z. Hussain Journal: Journal of Animal and Plant Sciences (JAPS) ISSN: 1018-7081 (Print), 2309-8694 (Online) Volume: 25 Issue: 1 Pages: 10-18 Year: 2015 DOI: NA URL: https://doi.org/NA Publisher: Pakistan Agricultural Scientists Forum Abstract:

Biotechnology has been directed primarily towards reproductive technology been employed for improvement of
industrial important enzymes which are foremost concern over the years for researchers. This review paper discusses the
exciting scientific and technical advances in molecular biology for the genetic improvement in thermotogales, the
hyperthermophiles with respect to xylose isomerase to meet the industrial demands. A thermo-acid stable enzyme
possesses neutral or slightly acidic pH optima and a higher affinity for glucose have a potential for industrial applications
for the production of high fructose corn syrup (HFCS). Xylose isomerases from Thermotoga sp are class II enzymes,
utilize a 1, 2 hydride shift catalytic mechanism, active only in the presence of Mn+2, Co+2 and Mg+2
. Recombinant xylose
isomerases from T. neapolitana existed both as homodimer as well as homotetramer have been produced under
mesophilic fermentation conditions, with a maximal activity at 97°C. Mutant enzyme in addition to this catalytically
active at pH 5.5 and showed 3.1 fold increased catalytic efficiency towards glucose. The addition of the carbohydrate
biding domain to Thermotoga’s xylose isomerase successfully immobilized the enzyme to chitin beads. The turnover
numbers (kcat) for glucose to fructose conversion for both unbound and immobilized mutants was greater than the wildtype enzyme.

Keywords: xylose isomerases, thermotogales, hyperthermophiles