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Thermodynamics of cyclophilin catalyzed peptidyl‐prolyl isomerization by nmr spectroscopy
Author(s) -
Videen John S.,
Stamnes Mark A.,
Hsu Victor L.,
Goodman Murray
Publication year - 1994
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360340203
Subject(s) - chemistry , isomerization , cyclophilin , catalysis , nuclear magnetic resonance spectroscopy , isomerase , enzyme , peptidylprolyl isomerase , cyclophilin a , stereochemistry , crystallography , organic chemistry , biochemistry , microbiology and biotechnology , biology , gene
One‐dimensional nmr exchange spectroscopy was carried out to determine thermodynamic parameters of cyclophilin‐induced cis ‐ trans isomerization of succinyl‐Ala‐Phe‐Pro‐Phe‐ p ‐nitroanilide. Rate measurements were possible at physiological temperatures. The k c / K m of rat cyclophilin was found to he 12.8 (±0.5) s −1 μ M −1 at 37°C, intermediate to previously reported values that used a coupled enzyme assay extrapolated to this temperature. Activation energies (Δ G ≠ ) for the uncatalyzed and catalyzed reaction at 37°C were found to be 19.7 and 17.1 kcal/mol, respectively, and were primarily due to an enthalpic barrier. © 1994 John Wiley & Sons, Inc.