Multiple Forms of Phenoloxidase

SUMMARY— The phenoloxidase system in the tissues of mushrooms, potatoes, and apples was investigated using a polyacrylamide electrophoretic technique. The enzyme system was shown to exhibit the phenomenon of multiple forms. The multiple form pattern obtained was highly characteristic for each individual species and variety studied, and substrate specificity was evident. The mushroom phenoloxidase system ( Agaricus campestris ) was shown to consist of at least nine distinct dl‐dopa‐reactive multiple forms, and at least three forms reacting with I‐tyrosine. Potatoes (var. Rural Russet) showed at least 11 bands of dl‐dopa activity, while apples (var. Golden Delicious) had at least three multiple forms of dl‐dopa activity. By introducing the “multiphase” gel electrophoretic technique a better resolution of the multiple forms was obtained. A group of closely related dl‐dopa multiple forms in mushrooms had the unique ability to withstand the temperature of 70°C for one hour. Sulfite, ethylenediamine‐tetraacetic acid (EDTA) and other treatments affected the multiple forms differently. Each multiple form behaved as an individual entity upon repeated elutions and electrophoreses.