PEROXIDASE AND PHENOLOXIDASE ACTIVITIES IN MUNG BEAN HYPOCOTYL CELL-WALLS

Three groups of cationic peroxidases were isolated from mung bean hypocotyl cell walls. A single active protein with a native M(r) of 64 000 was present in the first fraction, two with native M(r)s of 52 and 85 000 in the second one and only one with a M(r) of 152 000 in the third one (the most cationic one). This heavy molecule comprised three polypeptides, the M(r) of each was ca 48 000. The possible presence of so-called 'laccase' activity associated with the peroxidase was suggested by the strong oxidation of p-phenylenediamine-pyrocatechol in the absence of H2O2, by all the recovered fractions. These latter results were confirmed by cytochemical observations.