GLYCOSIDASES IN PLANT-TISSUES OF SOME BRASSICACEAE - SCREENING OF DIFFERENT CRUCIFEROUS PLANTS FOR GLYCOSIDASES PRODUCTION

Glycosidases namely myrosinase and beta-amylase, have been isolated fr om Brassicaceae. These enzymes were identified and estimated by the ra te of glucose and maltose formation from sinigrin (thioglucosinolate) and amylose (polysaccharides) hydrolysis, respectively. Their activiti es (U/g dry tissues) varied with the different species of the plant an d with the different parts of their tissues. Generally, they were high er in the germinated seeds (3.3-8.0 times) than in powdered or defatte d powdered dry seeds. The best amylase and myrosinase extracting solut ion for radish and white mustard germinated seeds was distilled water, and for turnip germinated seeds, it was 0.1M phosphate buffer, pH 6.0 . In the light, the optimum germination temperature for amylase produc tion or activation by radish and white mustard seeds was 25 degrees C, and for turnip seeds, it was 30 degrees C, whereas for myrosinase pro duction or activation by radish and turnip, 25-27 degrees C was the op timum temperature. The highest myrosinase activities in black mustard and radish defatted dry seeds were obtained by extraction with 1% NaCl at 27-30 degrees C and distilled water at 25-27 degrees C, after an i ncubation period of 4-6 h. Comparative studies indicated that fresh ra dish roots were the most potent amylase and myrosinase producers compa red with radish leaves or roots, stems, and leaves of turnip and cabba ge. Amylase and myrosinase were partially purified from water extracts of fresh radish roots by optimum precipitation with ammonium sulfate (100%). Some physicochemical properties were studied.