Soybean, -glucosidase

FUJITA H, YAMAGAMi T (2001) Fermented soybean-derived Touchi-extract with anti-diabetic effect via alpha-glucosidase inhibitory action in a long-term administration study with KKAy mice. Life Sci. 70 219-27. 

FUJITA H, YAMAGAMI T, OHSHIMA K (2001a) Long-teim ingestion of a fermented soybean-derived Touchi-extract with alpha-glucosidase inhibitory activity is safe and effective in humans with borderline and mild type-2 diabetes. JNutr. 131 2105-8. 

FUJITA H, YAMAGAMI T, OHSHIMA K (2001b) Fermented soybean-derived water-soluble Touch extract inhibits alpha-glucosidase and is antiglycemic in rats and humans after single oral treatments. /lyMr ". 131 1211-3. 

Intestinal microflora plays a key role in the metabolism and bioavailibility of isoflavones [86]. After ingestion, soybean isoflavones are hydrolyzed by intestinal glucosidases, which release the aglycones, daidzein and genistein, Fig. (16). 

In two studies (Lenz et al, 1987 Schocken et al, 1987) the water-soluble metabolites were separated by HPLC. Schocken et al (1987) separated 21 water-soluble metabolites from wheat straw, none of which amounted to >1.5% of the total residue. Lenz et al (1987) separated 20 water-soluble metabolites from soybean forage and 13 from soybean seed. Two of the five major forage metabolites were shown to be DADK O-glucosides by enzyme hydrolysis with a-glucosidase (DADK was detected). The other three major metabolites were resistant to hydrolysis with HC1. The 15 minor forage metabolites were also resistant to acid hydrolysis. 

During the production of soy milk, the natural [3-glucosidase present in soybean may convert some glucosides to the aglycone forms to contribute to an increase of objectionable flavor (Matsuura et al., 1989). The enzymes should be inactivated as rapidly as possible during or after soy milk extraction to improve the quality of soy milk. 

Suzuki, H., Takahashi, S., Watanabe, R. et al. (2006). An isoflavone conjugate-hydrolyzing p-glucosidase fi om the roots of soybean Glycine max) seedlings.. Journal of Biological Chemistry, 281,30251-30259. 

It is worth while noting, however, that Thomas, Whelan, and Peat found that sweet potato, crystalline jS-amylase or soybean, purified /3-amyl-ase will cleave pure amylose only 70% to completion. Cruder soybean preparations contain an additional factor ( Z enzyme ) which when added to the purified amylase will allow hydrolysis of the amylose to proceed to completion. The Z enzyme has been purified and found to have all the properties of a jS-glucosidase, and, in fact, emulsin will replace it. Consequently it appears that amylose contains one or more /3-linked glucose residues in the chain, or more likely attached to the chain at the free 2, 3, 5, or 6 position of an intra-chain glucose residue. Since it would probably take only one such /8-linked residue per chain to interrupt the progress of /3-amylase, it is not imusual that methylation studies have not detected it. The structure outlined previously for amylose may be modified somewhat to include these observations. 

Georgetti, S.R. Vicentini, F.T. Yokoyama, C.Y. Borin, M.F. Spadaro, A.C. Fonseca, M.J. Enhanced in vitro and in vivo antioxidante activity and mobilization of free phenoHc compounds of soybean flour fermented with different beta-glucosidase-producing fimgi. J. Appl. Microbiol, v. 106, p. 459-466,2009. 

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