Submitted to: Journal of Cereal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/20/2007
Publication Date: 5/1/2008
Citation: Biely, P., Leathers, T.D., Cziszarova, M., Vrsanska, M., Cotta, M.A. 2008. Endo-beta-1,4-xylanase inhibitors in leaves and roots of germinated maize. Journal of Cereal Science. 48(1):27-32. Interpretive Summary: Practical new methods are needed to produce sugar-based products from low-value agricultural residues such as corn fiber. Corn fiber is recalcitrant to digestion by microbial enzymes, and we discovered for the first time that the leaves and roots of germinating maize itself contain inhibitors of these enzymes. This work will be of interest to researchers developing new uses and value-added products from agricultural commodities and byproducts.
Technical Abstract: Extracts of both leaves and roots of germinating maize were found to contain endo-beta-1,4-xylanase inhibitors, previously reported only from whole maize meal. The inhibitors seem to be of the xylanase inhibitor protein (XIP) type, since they inhibit endoxylanases of families 10 and 11 and also show some other characteristics similar to XIP inhibitors described in other cereals. Inhibitors from leaves and roots appeared to be similar. Inhibitors extracted in the presence of dithiothreotol (DTT) exhibit a novel thermostability at low pH, with a half-life of more than 10 h at 100 deg C and pH 4.5. However, these inhibitors are less thermostable at higher pH levels. In the absence of DTT, an additional heat-labile but otherwise similar activity also was extracted.