Brazilian pink beans, trypsin

Recently, Whitaker and Sgarbieri (76) and Sgarbieri and Whitaker (77) reported there are at least four isoinhibitors of trypsin in Brazilian pink beans (Phaseolus vulgaris L. var. 

Figure 7. DEAE-cellulose chromatography of the trypsin-chymotrypsin isoinhibitors from Brazilian pink bean (Phaseolus vulgaris var. Rosinha G2. (Reproduced with permission from Ref 76. Copyright 1981, J. Food Biochem.j...

Table III. Values for the Binding of a-Chymotrypsin and Trypsin with Brazilian Pink Bean Inhibitors A,...

Considerable homology exists within the binding sites of several of the inhibitors as shown in Table VII. It has been suggested that trypsin inhibitors require a peptide sequence of Lys-X or Arg-X located within a loop of the protein closed by a disulfide bond (95,96). Reduction of disulfide bonds are known to be quite effective in destroying the inhibitory activity (77). For example, activity of the three isoinhibitors from Brazilian pink beans against both trypsin and chymotrypsin was lost when a specific disulfide bond, of the 18-21 disulfide bonds present, was reduced (77) SER appears to be a requirement of the binding site also for lysine-type inhibitors (Table VII). 

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