Bowman-Birk proteinase inhibitor

Chen, R, et al. (1992). Reactive sites of an anticarcinogenic Bowman-Birk proteinase inhibitor are similar to other trypsin inhibitors. /. Biol. Chem. 267,1990-1994. 

With soybean Bowman-Birk proteinase inhibitor, Odani and Ikenaka (1973) succeeded in separating two small fragments, one with 38 amino acids residues having a trypsin inhibitor activity, the other with 29 residues having a chymotrypsin inhibitor activity. However, reconstitution was not achieved. 

BowB Bowman-Birk type proteinase inhibitor E(P) 0(0) 0(0) 1SBW... 

Based on their sequence homology, disulfide connectivity, and cysteine location within the sequence and chemistry of the reactive site. Pis can be assigned to distinct families, as classified by Laskowski and Kato. Kunitz-type, Bowman—Birk-type, Potato type I and type II, and squash inhibitors are members of these families shown in Table 3. For inhibitors not falling into these classifications more families have been proposed. Pis can also be classified by their target/mode of action. Plants have been found to express Pis that target serine proteinases, cysteine proteinases, aspartic proteinases, and metallo-proteinases. Serine and cysteine protease inhibitors are the best-studied PIs. ... 

Among the EST database of ragi sequences, there are two groups of bifunctional proteinase inhibitor trypsin a-amylase from seeds of ragi sequences. The upper clade was further subdivided (Fig. 6.10). Wang et al. (2008) concluded that there was great diversity in the sequence of different Bowman-Birk inhibitors in emmer wheat both within and between populations. 

A family of cysteine proteinase inhibitors different from the cystatin superfamily was isolated from pineapple stem acetone powder. These inhibitors have a Mr of about 5800 and are composed of a longer (41 amino acids) and a shorter (11 amino acids) peptide chain connected with disulfide bonds [29]. The conserved sequence Gln-Val-Val-Ala-Gly of the cystatins is not present in these inhibitors, indicating a different mechanism of interaction. The bromelain inhibitor VI was found to share similar folding and disulfide bond connectivities with the Bowman-Birk trypsin/chymotrypsin inhibitor from soybean [30,31]. The physiological role of these inhibitors remains unclear. 

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