| Literature DB >> 7826325 |
N More1, R M Daniel, H H Petach.
Abstract
The stability of two enzymes from extreme thermophiles (glutamate dehydrogenase from Thermococcales strain AN1 and beta-glucosidase from Caldocellum saccharolyticum expressed in Escherichia coli) has been exploited to allow measurement of activity over a 175 degrees C temperature range, from +90 degrees C to -85 degrees C for the glutamate dehydrogenase and from +90 degrees C to -70 degrees C for the beta-glucosidase. The Arrhenius plots of these enzymes, and those for two mesophilic enzymes (glutamate dehydrogenase from bovine liver and beta-galactosidase from Escherichia coli), exhibit no downward deflection corresponding to the glass transition, found by biophysical measurements of several non-enzymic mesophilic proteins at about -65 degrees C and reflecting a sharp decrease in protein flexibility as the overall motion of groups of atoms ceases.Entities:
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Year: 1995 PMID: 7826325 PMCID: PMC1136422 DOI: 10.1042/bj3050017
Source DB: PubMed Journal: Biochem J ISSN: 0264-6021 Impact factor: 3.857