title: Unexpected high digestion rate of cooked starch by the Ct-maltase-glucoamylase small intestine mucosal α-glucosidase subunit.
abstract: For starch digestion to glucose, two luminal α-amylases and four gut mucosal α-glucosidase subunits are employed. The aim of this research was to investigate, for the first time, direct digestion capability of individual mucosal α-glucosidases on cooked (gelatinized) starch. Gelatinized normal maize starch was digested with N- and C-terminal subunits of recombinant mammalian maltase-glucoamylase (MGAM) and sucrase-isomaltase (SI) of varying amounts and digestion periods. Without the aid of α-amylase, Ct-MGAM demonstrated an unexpected rapid and high digestion degree near 80%, while other subunits showed 20 to 30% digestion. These findings suggest that Ct-MGAM assists α-amylase in digesting starch molecules and potentially may compensate for developmental or pathological amylase deficiencies.
authors.affiliation: Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Amy Hui-Mei
authors.initials: AH
authors.lastname: Lin
authors.forename: Buford L
authors.initials: BL
authors.lastname: Nichols
authors.forename: Roberto
authors.initials: R
authors.lastname: Quezada-Calvillo
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Avery
authors.forename: Lyann
authors.initials: L
authors.lastname: Sim
authors.forename: David R
authors.initials: DR
authors.lastname: Rose
authors.forename: Hassan Y
authors.initials: HY
authors.lastname: Naim
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Hamaker
mesh_terms: D000818:Animals; D003296:Cooking; D004063:Digestion; D005780:Gelatin / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D007413:Intestinal Mucosa / Q000201:enzymology / Q000378:metabolism; D007421:Intestine, Small / Q000201:enzymology* / Q000378:metabolism; D051379:Mice; D021122:Protein Subunits / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D013213:Starch / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism; D000520:alpha-Glucosidases / Q000235:genetics / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D011994:Recombinant Proteins; D005780:Gelatin; D013213:Starch; D000516:alpha-Amylases; D000520:alpha-Glucosidases