Antigenic determinants and reactive sites of a trypsin/chymotrypsin double-headed inhibitor from horse gram (Dolichos biflorus)

Sreerama, Yadahalli N. and Gowda, Lalitha R. (1997) Antigenic determinants and reactive sites of a trypsin/chymotrypsin double-headed inhibitor from horse gram (Dolichos biflorus). Biochimica et Biophysica Acta, 1343. pp. 235-242.

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Abstract

<p align="justify">The major proteinase inhibitor in horse gram (Dolichos biflorus) is a low molecular weight ~8500 Bowman–Birk inhibitor BBI, HGI-III, that inhibits both trypsin and chymotrypsin simultaneously. Analysis of the reactivity of the polyclonal antibodies raised against native HGI-III, with tryptic, lysylendoproteinase-C and CNBr peptides, in dot-blot assays, revealed the presence of three sequential epitopes (Asp¹–Lys¹⁴ (I), Leu³⁷–Lys⁶³ II and Asp⁵⁴–Lys⁷¹ (III)). Of these, epitope II and III occur consecutively in the sequence of HGI-III. The reactive site peptide bonds were identified by cleavage with catalytic quantities of either trypsin or chymotrypsin at acidic pH. The reactive site peptide bond for trypsin was found to be Lys²⁴–Ser²⁵, whereas for chymotrypsin it was Phe⁵¹–Ser⁵². The highly conserved reactive site loop residues of the Bowman–Birk inhibitors are also conserved in HGI-III. The less immunogenic peptide sequence,Leu³⁷–Lys⁶³, also contains the chymotrypsin reactive site. The recognition of this polypeptide by the immune system provides for a new strategy in the design of ideal, smaller proteinase inhibitors as cancer preventive agents.</p>

Item Type:	Article
Uncontrolled Keywords:	Antigenic determinant; Bowman–Birk inhibitor; Proteinase inhibitor; Trypsinrchymotrypsin inhibitor; Reactive site; (Dolichos biflorus)
Subjects:	600 Technology > 08 Food technology > 22 Legumes-Pulses
Divisions:	Dept. of Biochemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	17 Jun 2005
Last Modified:	28 Dec 2011 09:24
URI:	http://ir.cftri.res.in/id/eprint/80

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