amino acid availability of pea protein in poultry. Pea seed TI are predominantly of the Bowman-Birk inhibitor class, and qualitative and quantitative MEDChem Express 1-Naphthyl PP1 (hydrochloride) 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 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 Cetilistat cost 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. An alternative approach to reducing seed inhibitor activity has generated transgenic lines of soybean expressing a mutant BBI transgene where both active sites have been interrupted with an inserted Gly residue. These lines showed a significant reduction in the amount of seed inhibitor overall , likely as a consequence of the earlier expression of the transgene and a limited available sulphur amino acid pool. Soybean lines having combinations of th
