A lectin exhibiting antiproliferative activity on tumor cell lines but devoid of 
antifungal activity has been purified from Phaseolus vulgaris cv. Green Dragon 
no. 8 seeds. The lectin was a 60 kDa dimeric protein with two 30 kDa subunits. 
It was a glucosamine-specific lectin as implied from the inhibitory effect of 
glucosamine on hemagglutinating activity of the lectin. The steps for isolation 
of the lectin involved Affi-gel blue gel (affinity gel), Mono Q (anion 
exchanger), and Superdex 75 column (size exclusion). The lectin was purified 
20.8-fold from the crude extract of the beans. The purified lectin showed 
antiproliferative activity on breast cancer MCF7 cell line and nasopharyngeal 
cancer HONE1 and CNE2 cell lines, but a low activity on normal skin fibroblast 
HSF98 cell line. The lectin was shown to induce apoptosis on HONE1 cells, as 
indicated by increased phosphatidylserine externalization and mitochondrial 
depolarization. It also blocked HONE1 cell division and kept the cells at the 
G2/M phase of the cell cycle.