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Further characterisation of protease inhibitors from pigeon pea ( cajanus cajan (l) millsp) seeds
Author(s) -
Godbole Sangeeta A,
Krishna Thirumalai G,
Bhatia Chittaranjan R
Publication year - 1994
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740640314
Subject(s) - cajanus , trypsin , chymotrypsin , protease , biochemistry , chemistry , enzyme , helicoverpa armigera , phenylalanine , tyrosine , biology , amino acid , botany , larva , agronomy
Cajanus trypsin inhibitor (CTI) and Cajanus trypsin‐chymotrypsin inhibitor (CTCI) previously purified from cv TAT‐10 were further characterised. The modification of the inhibitors revealed the presence of lysine at the trypsin reactive site in both CTI and CTCI. Modification of tyrosine at the reactive site of CTCI did not abolish chymotrypsin inhibition suggesting the presence of leucine or phenylalanine as reported in other chymotrypsin inhibitors. CTCI did not contain tryptophan. Dissociation constants for the inhibitors with bovine trypsin were in the region of 0.69 nmol (CTCI) and 0.029 nmol (CTI). Although the protease inhibitors lost their inhibitory activity on exposure to 2‐mercaptoethanol they remained attached to the enzyme. The inhibitors were not very effective against the protease from Helicoverpa armigera which is a serious field pest of Cajanus. Dissociation constants for the inhibitors with the larval enzyme were in the region of 100 nmol.