ELECTROPHORETIC AND MOLECULAR-WEIGHT ANOMALIES ASSOCIATED WITH BROAD BEAN POLYPHENOLOXIDASE IN SDS-PAGE ELECTROPHORESIS

Purified broad bean polyphenoloxidase was subjected to electrophoresis under denaturing and partially denaturing conditions using five common SDS-PAGE electrophoresis systems. Boiled, but not reduced, samples showed a single major polypeptide of approximately 55 000 in all systems while boiled reduced samples showed two polypeptides of approximately 60 000-65 000 and 43 000-45 000. Samples which were not boiled or reduced showed variable Mr and polypeptide composition in each system. Reduced and unboiled samples showed multiple polypeptides, some of which were the result of apparent proteolysis. Comparisons of the five electrophoretic systems indicated apparent Mr differences and anomalous polypeptide patterns for the purified enzyme. © 1990.