Dataset Information

Unexpected high digestion rate of cooked starch by the Ct-maltase-glucoamylase small intestine mucosal ?-glucosidase subunit.

ABSTRACT: For starch digestion to glucose, two luminal ?-amylases and four gut mucosal ?-glucosidase subunits are employed. The aim of this research was to investigate, for the first time, direct digestion capability of individual mucosal ?-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 ?-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 ?-amylase in digesting starch molecules and potentially may compensate for developmental or pathological amylase deficiencies.

SUBMITTER: Lin AH

PROVIDER: S-EPMC3341394 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Publications

Unexpected high digestion rate of cooked starch by the Ct-maltase-glucoamylase small intestine mucosal α-glucosidase subunit.

Lin Amy Hui-Mei AH Nichols Buford L BL Quezada-Calvillo Roberto R Avery Stephen E SE Sim Lyann L Rose David R DR Naim Hassan Y HY Hamaker Bruce R BR

PloS one 20120501 5

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-amy ...[more]

PMID: 22563462

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Project description:Starch digestion in the human body is typically viewed in a sequential manner beginning with ?-amylase and followed by ?-glucosidase to produce glucose. This report indicates that the two enzyme types can act synergistically to digest granular starch structure. The aim of this study was to investigate how the mucosal ?-glucosidases act with ?-amylase to digest granular starch. Two types of enzyme extracts, pancreatic and intestinal extracts, were applied. The pancreatic extract containing predominantly ?-amylase, and intestinal extract containing a combination of ?-amylase and mucosal ?-glucosidase activities, were applied to three granular maize starches with different amylose contents in an in vitro system. Relative glucogenesis, released maltooligosaccharide amounts, and structural changes of degraded residues were examined. Pancreatic extract-treated starches showed a hydrolysis limit over the 12 h incubation period with residues having a higher gelatinization temperature than the native starch. ?-Amylase combined with the mucosal ?-glucosidases in the intestinal extract showed higher glucogenesis as expected, but also higher maltooligosaccharide amounts indicating an overall greater degree of granular starch breakdown. Starch residues after intestinal extract digestion showed more starch fragmentation, higher gelatinization temperature, higher crystallinity (without any change in polymorph), and an increase of intermediate-sized or small-sized fractions of starch molecules, but did not show preferential hydrolysis of either amylose or amylopectin. Direct digestion of granular starch by mammalian recombinant mucosal ?-glucosidases was observed which shows that these enzymes may work either independently or together with ?-amylase to digest starch. Thus, mucosal ?-glucosidases can have a synergistic effect with ?-amylase on granular starch digestion, consistent with a role in overall starch digestion beyond their primary glucogenesis function.

Dataset Information

Unexpected high digestion rate of cooked starch by the Ct-maltase-glucoamylase small intestine mucosal ?-glucosidase subunit.

Publications

Unexpected high digestion rate of cooked starch by the Ct-maltase-glucoamylase small intestine mucosal α-glucosidase subunit.

Similar Datasets

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