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Maltase-Glucoamylase (MGAM) and Sucrase-Isomaltase (SI) are α-glucosidases of the membrane of small intestinal enterocytes responsible for the digestion of dietary carbohydrates into glucose and other monosaccharides. MGAM and SI mRNA expression, protein synthesis and catalytic activity of MGAM and SI are found predominantly in enterocytes; however, they are also found in lower amounts in other non-intestinal tissues, notably blood leukocytes and kidney cells. Little information exists on the functions, the mRNA expression, the nature of the respective proteins and catalytic properties of MGAM and SI in non-intestinal tissues. To correlate the transcription, synthesis and activity of these enzymes, we measured the mRNA expression of MGAM and SI; the catalytic activities of maltase, sucrase, and isomaltase; and the presence of the respective proteins in small intestine and other tissues such as spleen, kidney and pancreas of 8 weeks old mice. Small intestine showed the highest level of mRNA expression of M...

Some polyphenols inhibit the activities of the four subunits of intestinal α-glucosidases, maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si). The use of polyphenols as modulators of the rate ...

Some polyphenolic compounds inhibit the intestinal alpha-glucosidases. However, it is not clear how those compounds affect the enzyme activity of the individual C or N terminals subunits of maltase-glucoamylase (Mgam) and sucrase-isomaltase (Si). ObjectiveTo modulate the enzymatic activity of the most active C terminal-Mgam (Ct-Mgam) and C terminal Si (Ct-Si) by selected polyphenols in order to control the glucose release from the starch digestion. MethodsMaltase activities of recombinant Ct-Mgam and Ct-Si subunits were measured by Tris Glucose- Oxidase (TGO) method. The reactions were stopped by TGO and the optical density was measured at 450 nm. ResultsMaltase activity of both enzymes was inhibited. IC50 values were 0.58 and 0.571 mM for caffeic acid, 0.039 and 0.014 mM chlorogenic acid, 0.139 and 0.213 mM for (+)-catechin hydrate, 0.383 and 0.177 mM for gallic acid, 0.041 and 0.014 mM for (−) epigallocatechin gallate for Ct-Si and Ct-Mgam, respectively. ConclusionsThe results indicate that the potencie...