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ediated by an exposed binding loop inserted into the convex active site of the target protease in a substrate-like manner. The resulting non-covalent enzyme-inhibitor complex renders the protease target inactive. The development and exploitation of near-isogenic pea lines with distinct alleles at the Tri locus controlling quantitative variation in protease inhibitory activity in pea seeds VX-702 clearly demonstrated the correlation between allelic variants and amino acid availability of pea protein in poultry. Pea seed TI are predominantly of the Bowman-Birk inhibitor class, and qualitative and quantitative genetic variants have been described within a five-fold range of inhibitory activity. Isoforms of the major pea seed-expressed BBI have been shown to be encoded by two genes, TI1 and TI2, that are closely linked, and they inhibit both trypsin and chymotrypsin. Minor pea BBI isoforms have predicted sites for trypsin inhibition only. The BBI proteins show considerable variation between and within species, where seed and vegetative isoforms may be distinguished. The expression of distinct genes, post-translational modification and differences in the oligomeric state of the inhibitors, are responsible for intra-specific variation and these may act in combination to affect inhibitory properties. The BBI are synthesised as precursors of approximately 100 amino acid residues, giving rise to mature proteins with a molecular Evacetrapib weight in the range 6000�C9000. Mature BBI contain two protease binding loops, located at opposite sides of the molecule, stabilised by a characteristic highly conserved array of disulphide bridges involving 14 cysteine residues. In combination, the disulphide bonds are likely responsible for the stability of BBI towards extreme conditions and for maintaining the structural and functional features of the binding sites. In order to gain knowledge of the structure-function relationships within protease inhibitors and their variants, and to enhance seed quality, natural variants and mutations have been sought in a number of species with some success. Null mutants or variants for seed protease inhibitors have been described in Glycine max and Glycine soja. A

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Author: calcimimeticagent