Viscosity dependence of the kinetics of the diffusion-controlled reaction of carbon monoxide and myoglobin.
The kinetics of the reaction of CO with myoglobin have been studied by laser flash photolysis in glycerol-water as a function of solvent viscosity and temperature. At high viscosities and low temperatures the second-order rate constant is inversely proportional to the viscosity raised to approximately the 0.5 power. This result parallels the behavior of the oxygen diffusion coefficient in glycerol-water. It is concluded that the reaction kinetics in high viscosity glycerol-water are largely diffusion controlled. At higher temperatures, though, the effect of simultaneous chemical activation control of the reaction is observed. The diffusion-controlled rate constant is 1.4 X 10(-3) of that predicted from simple von Smoluchowski theory based on diffusion coefficients and molecular radii. Several models with steric requirements for diffusion-controlled reactions are examined.
D002248:Carbon Monoxide; D004058:Diffusion; D005990:Glycerol; D007700:Kinetics; D009211:Myoglobin; D010782:Photolysis; D013696:Temperature; D014783:Viscosity; D014867:Water
D009211:Myoglobin; D014867:Water; D002248:Carbon Monoxide; D005990:Glycerol