Mucosal C-terminal maltase-glucoamylase hydrolyzes large size starch digestion products that may contribute to rapid postprandial glucose generation
Article first published online: 20 JAN 2014
© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Molecular Nutrition & Food Research
Volume 58, Issue 5, pages 1111–1121, May 2014
How to Cite
Lee, B.-H., Lin, A. H.-M., Nichols, B. L., Jones, K., Rose, D. R., Quezada-Calvillo, R. and Hamaker, B. R. (2014), Mucosal C-terminal maltase-glucoamylase hydrolyzes large size starch digestion products that may contribute to rapid postprandial glucose generation. Mol. Nutr. Food Res., 58: 1111–1121. doi: 10.1002/mnfr.201300599
- Issue published online: 22 APR 2014
- Article first published online: 20 JAN 2014
- Manuscript Accepted: 1 DEC 2013
- Manuscript Revised: 11 NOV 2013
- Manuscript Received: 14 AUG 2013
- USDA AFRI. Grant Number: 08-555-03-18793
- Canadian Institutes for Health Research. Grant Number: MOP111237
- Heart and Stoke Foundation of Ontario. Grant Number: NA-6305
- Glycemic spike;
- Mucosal α-glucosidases;
- Starch digestion
The four mucosal α-glucosidases, which differ in their digestive roles, generate glucose from glycemic carbohydrates and accordingly can be viewed as a control point for rate of glucose delivery to the body. In this study, individual recombinant enzymes were used to understand how α-glucan oligomers are digested by each enzyme, and how intermediate α-amylolyzed starches are hydrolyzed, to elucidate a strategy for moderating the glycemic spike of rapidly digestible starchy foods.
Methods and results
The C-terminal maltase-glucoamylase (ctMGAM, commonly termed “glucoamylase”) was able to rapidly hydrolyze longer maltooligosaccharides, such as maltotetraose and maltopentaose, to glucose. Moreover, it was found to convert larger size maltodextrins, as would be produced early in α-amylase digestion of starch, efficiently to glucose. It is postulated that ctMGAM has the additional capacity to hydrolyze large α-amylase products that are produced immediately on starch digestion in the duodenum and contribute to the rapid generation of glucose from starch-based meals.
The findings suggest that partial inhibition of ctMGAM, such as by natural inhibitors found in foods, might be used to moderate the early stage of high glycemic response, as well as to extend digestion distally; thereby having relevance in regulating glucose delivery to the body.