Author
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Sessa, David |
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Submitted to: International Food Science and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/7/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Soybean seed coats (hulls) which represent 8 percent of the whole soybean have an annual production of over 2 billion pounds. These seed coats at 3 cents per lb are used as a feed adjunct and as a source of fiber in food products. To add value to this byproduct of the soybean processing industry we have isolated and characterized a specific component (serine protease inhibitor) that has known anticarcinogenic and chemopreventive properties. Soybean seed coats represent a new and inexpensive source of serine protease inhibitors that will not only benefit the farmer by adding value and new use for seed coats but also the soy processing industry as well as drug firms who are currently evaluating serine protease inhibitors as potent anticarcinogens in humans. Technical Abstract: A protease inhibitor has been isolated from soybean seed coats and identified as a Bowman-Birk inhibitor (BBI). BBI, known to be an anticarcinogen as well as a chemopreventive agent, has two active sites - one specific for chymotrypsin inhibition (CTI) and the other specific for trypsin inhibition (TI). BBI suppresses cancer by it's ability to inhibit chymotrypsin. In addition to isolating and characterizing BBIs from soy seed coats we performed similar procedures to isolate and characterize BBIs from whole ground meal as well as dehulled flour in order to compare their respective CTI activities with TI activities. The techniques involved in extracting of BBIs from all three sources used the classic 60% aqueous ethanol extractions on defatted materials followed by acetone precipitations and isolation by ion exchange chromatographies on a CM Sephadex C-25 column eluted with a salt gradient. A commercial purified BBI standard was similarly chromatographed to define it's elution which occurred after 0.21M NaCl concentration. Identification of BBIs from all three sources included sodium dodecylsulfate polyacrylamide gel electrophoresis of column fractions compared with a purified BBI standard as well as specific colorimetric assays for CTI and TI activities. BBIs from soy seed coats are unique in that they possess a CTI:TI ratio of 5.27 as compared to 1.23 for BBIs from whole ground beans and 1.99 for BBIs from dehulled flour processed similarly. Soy seed coats with a production of over 2 billion pounds annually is an inexpensive, renewable resource for the production of this valuable component. |
