Purification and characterization of invertase inhibitors from Dioscorea rotundata tuber

Three invertase inhibitors (A), (B) and (C) from Dioscorea rotundata tuber were resolved on DEAE-cellulose ion exchanger. Two of the inhibitors, (B) and (C), were proteins and homogenous on polyacrylamide gels Mr 21,000 +/- 85 and 26,982 +/- 40/36,307 +/- 50 respectively. The inhibitors (B) and (C) were inactivated at 60 degrees C and had activity-pH optima at 5.2 and 6.4 respectively. (B) and (C) were non competitive inhibitors of invertase from yam and other sources.