The structure and peroxidase activity of myoglobin in alcoholic solvents

We present data on the peroxidase activity of equine skeletal myoglobin in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol. For experimentation in non-aqueous solvents the protein structure was stabilized through lyophilization from a solution of a buffer and 98% (dry weight) KCl. Myoglobin showed some solubility in methanol and its structure was probed with circular dichroism and UV-Vis absorption spectroscopies. Peroxidase activity of myoglobin toward the oxidation of o-phenylenediamine to 2,3-diaminophenazine was observed and measured in each of the listed solvents. The system in methanol showed the fastest initial rate of reaction. This initial rate in the other organic solvents was similar to the rate in water. However, myoglobin showed stable catalysis for a longer period of time in water. These results provide a first step forward in guiding the utilization of re-engineered myoglobin variants in non-aqueous solvents.70