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Modulation of starch digestion for slow glucose release through “toggling” of mucosal α‐glucosidases by acarbose
Author(s) -
Lee Byung-Hoo,
Eskandari Razieh,
Pinto B. Mario,
Nichols Buford L.,
Hamaker Bruce R.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.638.7
Subject(s) - acarbose , chemistry , postprandial , biochemistry , starch , hydrolysis , carbohydrate , maltase , digestion (alchemy) , food science , enzyme , endocrinology , diabetes mellitus , chromatography , biology
For digestion of starch, α‐amylase first hydrolyzes the starch structure to α‐limit dextrins (αLDx's). Complete hydrolysis to glucose then takes place through the combined action of mucosal maltase‐glucoamylase (MGAM) and sucrase‐isomaltase (SI), which have two subunits each (N‐ and C‐ terminal). In this study, we applied the concept of “toggling” through differential inhibition of subunits to examine control of glucogenesis from αLDx's with the aim of attaining slow glucose delivery to the body. Mammalian recombinant MGAM and SI subunits were individually reacted with αLDx's with varying concentrations of acarbose, a well known α‐glucosidase inhibitor. Released glucose amounts were analyzed for hydrolysis activity. Notably, results showed selective inhibitory effect on C‐terminal subunits by acarbose for starch digestion. Furthermore, K i values of C‐terminal subunits were lower than human α‐amylases which can be applied that certain amount of acarbose had inhibitory effect on the hydrolysis of αLDx's by C‐terminal subunits but not on α‐amylase for moderating glucogenesis. This result supports the concept of controlling starch digestion rate for slow glucose release through the “toggling” of activities of the mucosal α‐glucosidases by selective enzyme inhibition. Conceivably this approach could be used to treat Type II diabetes by extending postprandial blood glucose delivery to the body, and may apply as well to other metabolic syndrome‐associated diseases and conditions. This research was supported from Whistler Center for Carbohydrate Research and USDA/AFRI.