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

PLoS One. 2012;7(5):e35473. doi: 10.1371/journal.pone.0035473. Epub 2012 May 1.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cooking
  • Digestion
  • Gelatin / metabolism
  • Hot Temperature
  • Humans
  • Intestinal Mucosa / enzymology
  • Intestinal Mucosa / metabolism
  • Intestine, Small / enzymology*
  • Intestine, Small / metabolism
  • Mice
  • Protein Subunits / metabolism
  • Recombinant Proteins / metabolism
  • Starch / metabolism*
  • alpha-Amylases / metabolism
  • alpha-Glucosidases / genetics
  • alpha-Glucosidases / metabolism*

Substances

  • Protein Subunits
  • Recombinant Proteins
  • Gelatin
  • Starch
  • alpha-Amylases
  • alpha-Glucosidases