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Multiple molecular forms of finger millet subtilisin and amylase inhibitors
Author(s) -
Vaidyanathan V Viswanathan,
Virupaksha Tumkur K
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.2740540307
Subject(s) - subtilisin , trypsin , biochemistry , chemistry , chymotrypsin , sephadex , isoelectric point , enzyme , isoelectric focusing , chromatography
Nine varieties of finger millet ( Eleusine coracana Gaertn) including a wild form were screened for proteinase and α‐amylase inhibitory activities. Subtilisin inhibitory activity was present in all the varieties examined and was highest in the wild form, while the cultivated varieties had more trypsin inhibitory activity. Isoelectric focusing of a 60% ammonium sulphate fraction of the wild form, before and after complexing with subtilisin, showed multiple forms of subtilisin inhibitors one of which was also active against trypsin. Isoforms of finger millet subtilisin inhibitors were isolated from the ammonium sulphate fraction by ion exchange chromatography on DEAE‐Sephadex followed by SP‐Sephadex chromatography. Copurification of trypsin and α‐amylase inhibitory activities with subtilisin inhibitory activity was observed during cation exchange chromatography. PAGE analysis revealed them to be charge isomers with pI in the range 5·5–6·0. SDS–PAGE gave an estimate of 12 000 mol wt for each of them. Finger millet subtilisin inhibitors were more active on bacterial proteinases than on bovine trypsin and chymotrypsin.