Peptide mimics of the Bowman-Birk inhibitor reactive site loop

Bowman–Birk Inhibitors (BBIs) are small highly cross‐linked proteins that typically display an almost symmetrical “double‐headed” structure. Each “head” contains an independent proteinase binding domain. The realization that one BBI molecule could form a 1:1:1 complex with two enzymes led early workers to dissect this activity. Now, after three decades of research, it has been possible to isolate the antiproteinase activity as small (∼11 residues), cyclic, synthetic peptides, which display most of the functional aspects of the protein. More recently, it has been found that these peptide fragments are not just a synthetic curiosity—a natural 14‐residue cyclic peptide (SFTI‐1), which too encapsulates the BBI inhibitory motif, is found to occur in sunflowers. This article reviews the properties of BBI‐based peptides (including SFTI‐1) and discusses the features that are important for inhibitory activity. © 2002 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 66: 79–92, 2002