Epoxidation of aldrin by cell-free pea root preparations

The epoxidation of aldrin and factors influencing this reaction were studied with buffered, aqueous, cell-free preparations obtained from unbroken roots of laboratory-grown peas. Aldrin was available to the epoxidising enzymes at concentrations which far exceeded its reported water solubility. Under the experimental conditions, the optimum pH for the reaction was 6·5 using 0·02M phosphate buffer. The reaction rate increased up to 35°c, and decreased with higher temperatures. Various treatments indicated that the epoxidising factor was soluble, and not dependent on the presence of intact cells or cell organelles. No need could be shown for the cofactors NADPH₂ and Mg²⁺, which are required for animal microsomal oxidations. Inhibitor studies indicated both differences and similarities between the system studied here and animal microsomal preparations.