Protease inhibitors Bowman-Birk

Bowman-Birk protease inhibitors (BBIs) are among the best-studied serine protease inhibitors. They are found abundantly in dicotyledonous and monocotyledonous plants, with the former species expressing inhibitors of approximately 8 kDa in size with two reactive sites (double headed) and the latter expressing 8 kDa inhibitors with one reactive site and 16 kDa inhibitors with two reactive sites. Dicot BBIs feature 14 cysteine residues involved in disulfide bonds monocot BBIs have 10 cysteine residues. ... 

NT028 Witschi, H., and I. Espiritu. Development of tobacco smoke-induced lung tumors in mice fed Bowman-Birk protease inhibitor concentrate (BBIC). Cancer Lett 2002 183(2) 141-146. 

Legume (Fabaceae) Bowman-Birk protease inhibitor proteins (BBPIPs) are typically double-headed protease inhibitors with 14 cysteines (i.e. 7 S-S links) and molecular masses of 7-9 kDa. All the BBPIPs listed were isolated from seeds except for the Medicago sativa (alfalfa) leaf BBPIPs. For other details see the legend to Table 4. 

Plant species (common name) Bowman-Birk protease inhibitor proteins Protease specificity (IC50) fKd, Kil (reactive site) Ref. 

Various non-legume, non-Poaceae Bowman-Birk protease inhibitors have been isolated that have sequence homology to the other BBPIPs [137-140, 285-288] (Table 10). The Ananas BBPIPs are disulphide-linked heterodimers [137-140]. The Helianthus BBPIP SFTI-1 is a small cyclic peptide (cyclotide) [285, 286] whereas the Solanum tuberosum BBPIP is similar to the single-headed Poaceae BBPIPs [287, 288]. 

Table 10. Non-legume, non-cereal Bowman-Birk protease inhibitor homologues...

Angiotensin I converting enzyme Acquired immunodeficiency syndrome Aspartic protease inhibitor Bowman Birk protease inhibitor protein Chymotrypsin Cysteine protease inhibitor Endothelin-converting enzyme Elastase... 

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