Immunoassays of Soy Proteins

Abstract

Proteins of soybeans (Glycine max) are widely used in animal and human nutrition. In addition to the bulk of the seed storage proteins, which are classified as albumins and globulins, approximately 6% of soybean proteins are classified as inhibitors of trypsin and chymotrypsin and approximately 0.5% are sugar-binding lectins. The two major classes of inhibitors are the Kunitz trypsin inhibitor, which inhibits trypsin, and the Bowman-Birk inhibitor (BBI), which inhibits both trypsin and chymotrypsin. Unless removed or inactivated, these inhibitors and lectins can impair the nutritional quality and safety of soy-based diets. On the other hand, several studies suggest that BBI can also function as an anticarcinogen, possibly through interaction with a cellular serine protease. Good-quality soybean proteins contribute to the nutritional value of many specialty foods including infant soy formulas and milk replacers for calves, and provide texture to many processed foods. However, they may also induce occasional allergic responses in humans. This paper outlines immunoassays developed to analyze for soy proteins in different soybean lines, in processed foods, and in nonsoy foods fortified with soy proteins. An assessment of the current status of immunoassays, especially of enzyme-linked immunosorbent assays for soybean inhibitors of digestive enzymes, soy globulins, and soy lectins, demonstrates the usefulness of these methods in plant and food sciences and in medicine.

Effects of Coated Compound Proteases on Apparent Total Tract Digestibility of Nutrients and Apparent Ileal Digestibility of Amino Acids for Pigs

“…Most of the proteins in SBM are easily digested, but some proteins including glycinin, protease inhibitor and antigenic proteins are difficult to digest, especially for newly weaned pigs, which may damage intestinal health and impair immune function (Brandon and Friedman, 2002; Sun et al, 2008; Zhao et al, 2008; Wang et al, 2011a;b). Fortunately, with the developing of feed enzyme technologies, protease treatment of SBM is an alternative means to reduce the antigenic challenge of SBM and improve performance of animals (Rooke et al, 1998; Piao et al, 1999; Yu et al, 2007; Romero et al, 2013).…”

Probing the Soybean Bowman–Birk Inhibitor Using Recombinant Antibody Fragments

“…16,19,20 The antibody−antigen interaction has been well characterized, using enzyme-linked immunosorbent assays (ELISA), allowing nanomolar concentration of active BBI in soybean cultivars to be successfully detected. 21 Furthermore, it is the only anti-BBI IgG available commercially for the specific detection of BBI in soy products. Its paratope targets the tryptic loop (conformational epitope) of BBI.…”

Nutritional and Bioactive Compounds of Soybean: Benefits on Human Health

“…However, sequence homologies between these 2 groups (G1, G2, G3 and G4, G5) are only about 50% (Nielsen, 1996). Whole soybean contains about 7-9% of protease inhibitors that are in the grain cotyledon (Brandon & Friedman, 2002;Esteves et al, 2010;Penha et al, 2007). There are two types of inhibitors: the Kunitz trypsin (KTI), and trypsin inhibitor and chymotrypsin Browman-Birk (BBI) (Miura et al, 2005;Monteiro et al, 2004;Monteiro et al, 2003).…”