Bowman-Birk trypsin inhibitor

Inhibition of trypsin is another mechanism of activity recently discovered in plant defensins. CfDl and CfD2 from Cassia fistula were the first plant defensins to be identified as trypsin inhibitors. Cp-thionin from cowpea was more recently discovered to have inhibitory potency against trypsin. Searches of protein sequence databases have yielded a number of other plant proteins annotated as trypsin inhibitors or potential trypsin inhibitors. These annotations were most likely made on the basis of sequence similarities with other known trypsin inhibitors, namely the Bowman—Birk trypsin inhibitor. Since the actual framework of the disulfide bonds is not known, it is possible that structure and therefore activity differ from this prototype framework. ... 

The Bowman Birk trypsin inhibitor is the smaller trypsin inhibitor with MW -S.OkD and binding sites for trypsin and chymotrypsin (Birk, 1985). BBI is more heat-stable than the Kunitz inhibitor probably resulting from its great proportion of disulfide cross-linking at 7 per mole BBI. Although BBI is present in much lower amounts in raw soybeans, its relative heat stability may be the main reason for the residual STI activity in moist-heated soybean protein products. Friedman and Brandon (2001) reported about 7 pg/mL BBI in soy-based infant formula as measured by ELISA while Dipietro and Liener (1989) reported <0.1 pg/mg (their limit of detection by ELISA) for SIR... 

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. 

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. 

K. Hatano, M. Kojima, M. Tanokura, and K. Takahashi. Solution structure of bromelain inhibitor VI from pineapple stem structural similarity with Bowman-Birk trypsin/chymotrypsin inhibitor from soybean. Biochemistry 35 5379 (1996). 

Inhibitors of the Bowman-Birk type have a relative molecular weight of about 6-10 kDa, a higher number of disulfide bridges, and exhibit specificity against trypsin and chymotrypsin, as they contain two independent binding sites in the molecule. Bowman-Birk type inhibitors belong to the most common inhibitors. They occur in legumes, cereals, pseudocereals, potatoes and some other materials. 

The Bowman-Birk trypsin-chymotrypsin inhibitor (BBI) from soybean has been proposed as anticarcinogenic drugs. The BBI inhibited the growth of human colorectal adenocarcinoma HT29 cells in vitro (Clemente et al., 2005). 

Our studies have shown the cytotoxic effect of trypsin inhibitors. Similar results were obtained in cell culture H28 of malignant mesothelioma. When adding Bowman-Birk protease inhibitor from soybeans at concentrations of 200-400 pg/ml Inhibition of cell growth (Kashiwagi et al, 2011). Currently, research is continuing to explore mechanisms of toxicity. Apparently, this may be related to the processes of apoptosis (Troncoso et al., 2009). 

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. 

Some of the best investigated anti-nutrients are the enzyme inhibitors present in legumes and other plants. The Bowman-Birk and the Kunitz inhibitors of trypsin and other proteases are among the best characterized. In contrast to the non-specific and widespread influences of tannins and lectins (Carmona, 1996), the Bowman-Birk, Kunitz and other such inhibitors target specific enzymes. Corresponding with this, proteases and other digestive enzymes vary in sensitivity to the different inhibitors. 

II Soybean trypsin inhibitor (Bowman-Birk-type) PF00228... 

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. 

Chymotrypsin (3.4.21.1) Avazyme, Chyrnar, Enzeon, Quimar Calcium (3-Phenylpropionate [26], aprotinin [5,44,45,141-144], Bowman-Birk inhibitor [7,141,145], benzyloxycarbonyl-Pro-Phe-CHO [43], chicken ovoinhibitor [47], chymostatin [3,141], DFP [26], FK-448 [3], PMSF [26], polycarbophil-cysteine [67], soybean trypsin inhibitor [5,7,51], sugar biphenylboronic acids complexes [146], poly(acrylate) derivatives [49]... 

Aprotinin is a polypeptide consisting of 58 amino acid residues derived from bovine lung tissues and shows inhibitory activity toward various proteolytic enzymes including chymo-trypsin, kallikrein, plasmin, and trypsin. It was also one of the first enzyme inhibitors used as an auxiliary agent for oral (poly)peptide administration. The co-administration of aprotinin led to an increased bioavailability of peptide and protein drugs [5,44,45], The Bowman-Birk inhibitor (71 amino acids, 8 kDa) and the Kunitz trypsin inhibitor (184 amino acids, 21 kDa) belong to the soybean trypsin inhibitors. Both are known to inhibit trypsin, chymotrypsin, and elastase, whereas carboxypeptidase A and B cannot be inhibited [7,46],... 

Chymotrypsin Aprotinin, benzyloxycarbonyl-Pro-Phe-CHO, Bowman-Birk inhibitor, chicken ovoinhibitor, chymostatin, 4-(4-isopropyl piperadinocarbonyl)phenyl 1,2,3,4-tetrahydro-l-naphthoate methanesulphonate, soybean trypsin inhibitor... 

The Bowman-Birk type protease inhibitors represent a class of low molecular weight, cysteine-rich proteins found in legume seeds (.10). The major Bowman-Birk inhibitor in soybean seeds is a double-headed protein capable of blocking the activity of both trypsin and chymotrypsin. This protein represents approximately 4% of the total protein in soybean seeds (1J ). In contrast to the soybean trypsin inhibitor (Kunitz), the "double-headed inhibitor (referred to as BB) is typical of protease inhibitors present in a large number of legume seeds for example, peanuts (12) chick peas (33)5 kidney beans (3JO adzuki beans (33) lima beans (16). 

The Bowman-Birk inhibitor also blocks the transformation of C H/10T1/2 cells (18). This raises the speculation that BB may represent a direct acting nutritionally relevant anticarcinogen particularly in the case of colon cancer. In this regard it was recently reported that e-aminocaproic acid (a trypsin inhibitor) inhibits dimethylhydrazine-induced colon tumors in mice (22). 

The Bowman-Birk soybean trypsin and chymotrypsin inhibitor modulates the growth of human colon and breast cancer cells. 

Polypeptides Aprotinin (Kimura et al. 1996, Saffran et al. 1988, Yamamoto et al. 1994), Bowman-Birk inhibitor, Kunitz trypsin inhibitor, chicken egg white trypsin inhibitor (Reseland et al. 1996, Ushirogawa 1992), chicken ovoinhibitor (Scott et al. 1987), human pancreatic trypsin... 

Trypsin/chymotrypsin Bowman-Birk inhibitor from Lens culinaris L. culinaris... 

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