Photoperturbation-relaxation approach to the kinetics of cooperative ligand binding by heme proteins
A small perturbation technique for measuring the ligand photodissociation and recombination kinetics of heme proteins has been developed. The Photodissociation Perturbation Relaxation (PPR) method involves perturbing the photodissociation rates of ligand-heme systems maintained at photointensity-dependent, nonequilibrium photostationary states. The theoretical and experimental datails of the PPR method are presented herein. A formalism for computing PPR amplitudes and time constants for complex reaction mechanisms for the eigenvectors and eigenvalues of the appropriate linear rate equations is derived; a FORTRAN code embodying this formalism is presented. PPR kinetics measurements obtained for the carbon monoxide derivatives of sperm whale myoglobin and human hemoglobin are presented. CO-hemoglobin combination rate constants and photodissociation quantum efficiencies, determined via fitting model-derived relaxation eigenmodes to PPR transients are presented.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6090429
- Report Number(s):
- ORNL/TM-8637; ON: DE83014601
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BIOCHEMICAL REACTION KINETICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
COMPUTER CALCULATIONS
COMPUTER CODES
DECOMPOSITION
HEME
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
KINETICS
LIGANDS
MEASURING METHODS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
S CODES