The lectin from leaves of Japanese cycad, Cycas revoluta Thunb. (gymnosperm) is a member of the jacalin-related family.

A novel lectin was isolated from leaves of the Japanese cycad, Cycas revoluta Thunb. (gymnosperm), and its characteristics including amino acid composition, molecular mass, carbohydrate binding specificity and partial amino acid sequences were examined. The inhibition analysis of hemagglutinating activity with various sugars showed that the lectin has a carbohydrate-binding specificity similar to those of mannose recognizing, jacalin-related lectins. Partial amino acid sequences of the lysylendopeptic peptides shows that the lectin might have a repeating structure and belong to the jacalin-related lectin family.