Soy Bean Trypsin Inhibitor

Figure 1. Peptide maps of PVDF-bound soy bean trypsin inhibitor (190 pmol) digested with endoproteinase Glu-C in the presence of 50 pi of A) 1% RTX-IciO/lOO mM Tris pH, 8.0, B) 1% octylglucopyranoside/100 mM Tris pH, 8.0, and C) 1% heptylglucopyranoside/100 mM Tris, pH 8.0 as described in Materials and Methods. Digestion in the presence of 1% decylglucopyranoside was not analyzed by HPLC due to the presence of micelles.

Sol-gel-immobilized trypsin activity towards small substrates was not inhibited either by soy bean trypsin inhibitor (201 kDa). Poly-L-lysine of molecular size above M. = 29.6 kDa had no effect on immobilized trypsin activity, while in the range of = 1.5-8.0 kDa this polymer inhibited the biological glass activity to the same extent, as that of the soluble enzyme. All this indicates effective pore sizes of about 2-4 nm (30),... 

We therefore examined whether ascitic formation could be blocked by the soy bean trypsin inhibitor SBTI, which is a specific inhibitor of kallikrein. SBTI was administered ip for 14 days beginning from the day of ip tumor inoculation. The results indicate significantly less accumulation of the fluid with SBTI (Fig.5). We concluded that enhanced vascular permeability occurred in tumor tissue partly because of the potent permeability factor, Kinin. ... 

Phosphorylation and hydrolysis were measured after chloroplasts (40 yg were pretreated with trypsin (4 yg ml ), chymotrypsin (30 yg ml ), pH 7.8, ten5>erature 23°C. In the subsequent dark period additions were 100 yl Soy Bean tirypsin inhibitor, methyl viologen 1.0 yM, ADP or ATP 0.5 mM. 

Trypsin inhibitors Serine proteases 10-100 pg/ml Trypsin inhibitor from soy beans is instable in alkaline solutions... 

Trypsin inhibitors (TI) are present in many plant foods, but soybeans are one of the most widely consumed crops containing these antinutrients. TI prevent protein digestion and eventually consumption can lead to pancreatic hypertrophy or poor growth. Higher extrusion temperatures (138—154°C) were required for conventional soybeans to achieve the same nutritional quality as extruded Kunitz trypsin inhibitor-free beans processed at 121—138°C (Zhang et ai, 1993). Soybeans extruded at these temperatures were comparable to commercial solvent-extracted soy meal. Urease index decreased and chick growth performance increased as extrusion temperature was raised. 

Birk, Y. (1961). Purification and some properties of a highly active inhibitor of trypsin and a-chymotrypsin from soy beans. Biochim. Biophys. Acta 54, 378-381. 

---