ISOLATION AND CHARACTERIZATION OF TRYPSIN INHIBITOR FROM THE WATER FERN, AZOLLA PINNATA R.Br.

Trypsin inhibitor from water fern (Azolla pinnata R. Br.) was isolated and characterized. Extraction of Azolla leaf meal in NaCl (0.15 M) rendered a higher recovery of trypsin inhibitor compared to other solvents tested (P < 0.05). The extraction time affected the inhibitor recovery significantly (P < 0.05). The extraction time of 3 h was optimum for the recovery of trypsin inhibitor. Based on inhibitor activity of a zone separated by electrophoresis, the molecular mass of the inhibitor from Azolla leaf was 21 kDa. The partially purified inhibitor was heat stable up to 10 min at 90C, at pH 7.0. High activity was also retained over a wide pH range (4–8) at 37C.