Abstract
Properties of polyphenol oxidase purified from Garland Chrysanthemum were investigated and the effect of inhibitors on enzyme activity and on the browning was discussed in this paper.
The results were summarized as follows :
1) Polyphenol oxidases in Garland chrysanthemum were fractionated to four kinds, called E-I, II, III and IV, by DEAE cellulose column chromatography. They exhibited 'different migrations on Disk-electrophoresis. Specific activities of enzymes purified were increased to about 580-830 times as much as that of juice.
2) Optimum pH for E-I, II, III and IV are 5.0-6.0, 5.0, 6.0 and 6.1, respectively. E-II was specific for pyrocatechol, whereas E-III oxidized well both chlorogenic acid and monophenol, like as tyrosine.
3) The activity of the above two enzymes was little inhibited by NaCl, while inactivated by DIECA, thiourea, L-cysteine and reduced glutathione.
4) Based on the investigation as to the mechanism of various inhibitions by ultraviolet spectra and paper chromatography, it was assumed that the inhibitions by cysteine and glutathione were produced by the formation of chlorogenic acid-cysteine or chlorogenic acid-glutathione complex having yellow fluorescence.
