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Characterisation of a trypsin/chymotrypsin inhibitor from jack fruit ( Artocarpus integrifolia ) seeds
Author(s) -
Annapurna S Sai,
Ramadoss Candadai S,
Prasad D Siva
Publication year - 1991
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.2740540412
Subject(s) - trypsin , chymotrypsin , amino acid , trypsin inhibitor , chemistry , biochemistry , artocarpus , enzyme , biology , botany
Abstract Jack fruit seed ( Artocarpus integrifolia Hook f) trypsin inhibitor (JSTI) was found to be rich in acidic amino acids and devoid of free thiol groups. The N‐terminal and C‐terminal amino acids of JSTI were aspartic acid and scrine, respectively. The inhibitor was stable under conditions of extremes of pH (3·0–12·0), at high temperatures and in the presence of denaturing agents. JSTI showed a non‐competitive type of inhibition with K i values of 0·48 ± 0·17 n M and 0·16 ± 0·04 n M for trypsin and chymotrypsin, respectively. The JSTI–trypsin complex exhibited chymotrypsin inhibitory activity suggesting the ‘double‐headed’ nature of the inhibitor. Chemical modification of lysine residues resulted in loss of trypsin and chymotrypsin inhibitory activities of JSTI indicating that amino groups are essential for activity.