Factors affecting endo-beta-mannanase activity in the endosperms of fenugreek and carob seeds

Endosperms of fenugreek and carob which have been leached following their isolation exhibit increased activity of endo-beta-mannanase, part of which is released into the surrounding incubation medium. This activity was suppressed by the addition to the endosperms of abscisic acid or endosperm/seed coat leachate. The leachate from carob inhibited the increase of endo-beta-mannanase activity in fenugreek and that from fenugreek inhibited enzyme activity in carob but more weakly; neither of these leachates inhibited the production of alpha-amylase in wheat endosperm. Polyethylene glycol-induced stress on non-leached endosperms inhibited endo-beta-mannanase production, but not when the stress was applied following endosperm leaching. However, the stress did reduce the amount of enzyme released into the surrounding incubation medium. Several isoenzymes of mannanase could be detected on isoelectric focusing activity gels in the endosperms of both fenugreek and carob, but their pls differed between the two species. When activity was suppressed by ABA or leachate, all pi forms declined equally.