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Thermodynamics of Enzyme-catalyzed Reactions

Summary:

To develop the thermodynamic data and methodology required for effective bioprocess engineering.

Description:

Current efforts are focused on industrially important biotransformation problems such as those found in hydrogenation, hydroxylation, aromatic amino acid metabolic pathways, and biofuel applications. The methods used include calorimetry, chromatography, enzymology, and spectrophotometry. The quantities that are measured, apparent equilibrium constants K¢ and calorimetrically determined enthalpies of reaction ΔrH(cal), are used to calculate values of standard equilibrium constants K and enthalpies of reaction ΔrH°. These values, in turn, can be used in an equilibrium model (http://xpdb.nist.gov/enzyme_thermodynamics/download.html), to predict the position of equilibrium and extent of reaction for a biochemical reaction as a function of temperature, pH, pMg, and ionic strength.

Major Accomplishments:

  • The Thermodynamics of Enzyme-Catalyzed Reactions Database (http://xpdb.nist.gov/enzyme_thermodynamics/) has been converted to a fully relational database by using the Oracle database management software. It can now be searched by users in an extremely wide variety of ways. The most recent update was published in the Journal of Physical and Chemical Reference Data.
  • The thermodynamics of the hydrolysis reactions of 1-naphthyl acetate, 4-nitrophenyl acetate, and 4-nitrophenyl a-L-arabinofuranoside have been studied by use of HPLC and microcalorimetry. The first two hydrolysis reactions are catalyzed by acetylxylan esterase and the third reaction by a‑N‑arabinofuranosidase. These reactions were selected for study due to their importance in efficient biomass utilization.
  • We are working with the IUPAC and the IUBMB on Recommendations for Terminology and Databases for Biochemical Thermodynamics(http://www.chem.qmul.ac.uk/iubmb/thermod2/). These recommendations also deal with the reporting of experimental results in the literature.
  • We are working to develop methods needed for thermodynamic network calculations for biochemical substances and reactions that can be used to calculate the standard formation properties of specific, ionic biochemical species.

End Date:

ongoing

Lead Organizational Unit:

mml

Staff:

Robert Goldberg
Yadu Tewari
TN Bhat

Contact

General Information:
Steven Choquette
301-975-3096 Telephone
steven.choquette@nist.gov

100 Bureau Drive, M/S 8312
Gaithersburg, MD 20899-8312