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Title: Mechanisms of Glycerol Dehydration

Abstract

No abstract prepared.

Authors:
; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
889344
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry A; Journal Issue: 18
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 59 BASIC BIOLOGICAL SCIENCES; DEHYDRATION; GLYCEROL; CHEMISTRY; BIOLOGY; BioPower

Citation Formats

Nimlos, M. R., Blanksby, S. J., Qian, X., Himmel, M. E., and Johnson, D. K. Mechanisms of Glycerol Dehydration. United States: N. p., 2006. Web. doi:10.1021/jp060597q.
Nimlos, M. R., Blanksby, S. J., Qian, X., Himmel, M. E., & Johnson, D. K. Mechanisms of Glycerol Dehydration. United States. doi:10.1021/jp060597q.
Nimlos, M. R., Blanksby, S. J., Qian, X., Himmel, M. E., and Johnson, D. K. Sun . "Mechanisms of Glycerol Dehydration". United States. doi:10.1021/jp060597q.
@article{osti_889344,
title = {Mechanisms of Glycerol Dehydration},
author = {Nimlos, M. R. and Blanksby, S. J. and Qian, X. and Himmel, M. E. and Johnson, D. K.},
abstractNote = {No abstract prepared.},
doi = {10.1021/jp060597q},
journal = {Journal of Physical Chemistry A},
number = 18,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • Highlights: Black-Right-Pointing-Pointer Catalytic mechanisms of thermophilic-mesophilic enzymes may differ. Black-Right-Pointing-Pointer Product release is rate-determining for thermophilic IGPS at low temperatures. Black-Right-Pointing-Pointer But at higher temperatures, proton transfer from the general acid is rate-limiting. Black-Right-Pointing-Pointer Rate-determining step is different still for mesophilic IGPS. Black-Right-Pointing-Pointer Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order tomore » cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 Degree-Sign C for thermophilic IGPS, near its adaptive temperature (75 Degree-Sign C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO{sub 2} release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.« less
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