Abstract
The dynamics of the enthalpy and volume changes found in the photodissociation of CO from sperm whale carboxymyoglobin and two site-directed mutants in which arginine-45 is replaced by glycine and asparagine are examined by photoacoustic calorimetry. An intermediate is observed whose lifetime at 20°C is 700 ns. The enthalpy of the intermediate increases by ~7 kcal/mol upon replacing arginine-45 with either asparagine or glycine. These observations support recent proposals that an arginine-45 salt bridge is broken upon ligand dissociation.
Original language | English (US) |
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Pages (from-to) | 6741-6746 |
Number of pages | 6 |
Journal | Biochemistry |
Volume | 29 |
Issue number | 28 |
DOIs | |
State | Published - Jan 7 1990 |
ASJC Scopus subject areas
- Biochemistry