A serine Kunitz protease inhibitor was isolated from
the semi-mature leaves of Terminalia arjuna, a host
plant for Antheraea mylitta, using ammonium sulphate
fractionation, gel permeation chromatography and
trypsin–sepharose affinity chromatography. A 29-fold
purification of T. arjuna Trypsin Inhibitor (TaTI) with
a yield recovery of 3.2% was achieved. The purified
protease inhibitor (TaTI) was resolved into a single
protein band corresponding to molecular weight of
19.0 kDa on 12% SDS–PAGE under non-reducing
conditions, whereas an additional band of 21.5 kDa was
observed when the same fraction was resolved on
SDS–PAGE under reducing conditions in the presence
of 2-mercaptoethanol. TaTI inhibited both trypsin and
chymotrypsin, but showed higher affinity for trypsin
compared to chymotrypsin. However, it is more effective
on bovine trypsin than midgut trypsin of tasar
silkworm. TaTI retains its activity over a wide range
of temperatures (0–100°C) and pH (2.0–8.0), with pH
optimum of 8.0. These observations indicate that TaTI
is not only specific to tasar silkworm but also to bovine
serine proteases. Hence it can be considered as a
generalist protease inhibitor