The purification and partial enzymology characteristics of polyphenol oxidase from Lonicera japonica (LjPPO) were studied in this paper. The crude enzyme solution was purified in turn by ammonium sulfate, dialysis, and DEAE-cellulose ion-exchange chromatography after preliminary treatments. Purification resulted in 31-fold enrichment and its molecular weight was estimated to be similar to 49 kDa exhibited on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The pH for optimal conditions of LjPPO was 7.5, and the temperature was 25 degrees C, in addition, the inhibitive effects of inhibitors were enhanced positively with increasing of the concentration. Moreover, crude enzyme solution showed diphenolase activity toward catechol, L-dopa and chlorogenic acid rather than monophenolase and tri-phenolase activity, and the best substrate was catechol because of the highest V-max/K-m value. However, the oxidation of diphenol related to browning significantly, so the data obtained in this research provided theoretical basis for the prevention of enzymatic browning of L. japonica during processing. (C) 2012 Elsevier Ltd. All rights reserved.