Maltase‐Glucoamylase Modulates Gluconeogenesis and Sucrase‐Isomaltase Dominates Starch Digestion Glucogenesis

Diaz‐Sotomayor, Maricela; Quezada‐Calvillo, Roberto; Avery, Stephen; Chacko, Shaji; Yan, Like; Lin, Amy Hui‐Mei; Ao, Zihua; Hamaker, Bruce R.; Nichols, Buford L.

doi:10.1097/mpg.0b013e3182a27438

Cited by 45 publications

(43 citation statements)

References 25 publications

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“…This inhibitory activity was later localized to the C-terminal 'glucoamylase' subunit (Quezada-Calvillo et al, 2008). It has been proposed that maltase-glucoamylase is responsible for the rapid hydrolysis at low-starch intakes, whereas sucrase-isomaltase provides sustained hydrolysis at high-starch intakes (Diaz-Sotomayor et al, 2013). This greater overall activity of sucrase-isomaltase is consistent with the relative abundances of the proteins in that sucrase-isomaltase is approximately 3-fold greater than maltase-glucoamylase (Amiri and Naim, 2017).…”

Section: Mucosal Carbohydrasesmentioning

confidence: 78%

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Harmon

Swanson

2020

Animal

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Pregastric fermentation along with production practices that are dependent on high-energy diets means ruminants rely heavily on starch and protein assimilation for a substantial portion of their nutrient needs. While the majority of dietary starch may be fermented in the rumen, significant portions can flow to the small intestine. The initial phase of small intestinal digestion requires pancreatic α-amylase. Numerous nutritional factors have been shown to influence pancreatic α-amylase secretion with starch producing negative effects and casein, certain amino acids and dietary energy having positive effects. To date, manipulation of α-amylase secretion has not resulted in substantial changes in digestibility. The second phase of digestion involves the actions of the brush border enzymes sucrase-isomaltase and maltase-glucoamylase. Genetically, ruminants appear to possess these enzymes; however, the absence of measurable sucrase activity and limited adaptation with changes in diet suggests a reduced capacity for this phase of digestion. The final phase of carbohydrate assimilation is glucose transport. Ruminants possess Na+-dependent glucose transport that has been shown to be inducible. Because of the nature of pregastric fermentation, ruminants see a near constant flow of microbial protein to the small intestine. This results in a nutrient supply, which places a high priority on protein digestion and utilization. Comparatively, little research has been conducted describing protein assimilation. Enzymes and processes appear consistent with non-ruminants and are likely not limiting for efficient digestion of most feedstuffs. The mechanisms regulating the nutritional modulation of digestive function in the small intestine are complex and coordinated via the substrate, neural and hormonal effects in the small intestine, pancreas, peripheral tissues and the pituitary—hypothalamic axis. More research is needed in ruminants to help unravel the complexities by which small intestinal digestion is regulated with the aim of developing approaches to enhance and improve the efficiency of small intestinal digestion.

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Section: Mucosal Carbohydrasesmentioning

confidence: 78%

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Harmon

Swanson

2020

Animal

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“…24 Comparing the contribution of MGAM and SI to carbohydrate digestion, a recent research shows that, at low oligomer concentrations, MGAM is ten times more active than SI, but at high concentrations, MGAM experiences substrate inhibition while SI is not affected. With the finding of a dominant role played by SI in mucosal maltase activity and early rate of starch digestion, 30 the loss of debranching activity of isomaltase of SI makes it difficult to produce linear maltooligosaccharides that can be rapidly digested by MGAM. 27 This substrate 'brake' effect suggests that the total digestion rate of carbohydrate by MGAM can be regulated, and carbohydrate with certain molecular structures might be used to modulate carbohydrate digestion to achieve the desired rate of glucose release.…”

Section: Coordination Of Carbohydrate Property and Enzyme Activitymentioning

confidence: 99%

Gut feedback mechanisms and food intake: a physiological approach to slow carbohydrate bioavailability

et al. 2015

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Glycemic carbohydrates in foods are an important macronutrient providing the biological fuel of glucose for a variety of physiological processes. A classification of glycemic carbohydrates into rapidly digestible carbohydrate (RDC) and slowly digestible carbohydrate (SDC) has been used to specify their nutritional quality related to glucose homeostasis that is essential to normal functioning of the brain and critical to life. Although there have been many studies and reviews on slowly digestible starch (SDS) and SDC, the mechanisms of their slow digestion and absorption were mostly investigated from the material side without considering the physiological processes of their in vivo digestion, absorption, and most importantly interactions with other food components and the gastrointestinal tract. In this article, the physiological processes modulating the bioavailability of carbohydrates, specifically the rate and extent of their digestion and absorption as well as the related locations, in a whole food context, will be discussed by focusing on the activities of the gastrointestinal tract including glycolytic enzymes and glucose release, sugar sensing, gut hormones, and neurohormonal negative feedback mechanisms. It is hoped that a deep understanding of these physiological processes will facilitate the development of innovative dietary approaches to achieve desired carbohydrate or glucose bioavailability for improved health.

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“…The symptoms result from defective glucosidase (disaccharidase) activity of the SI enzyme in the small intestine. 12 This enzyme is key to the degradation of starch and sugars digested daily, 13 and its functional impairment leads to colonic accumulation of unabsorbed carbohydrates causing osmotic diarrhoea. At the same time, this induces a shift in gut microbiota-associated activities of carbohydrate metabolism and fermentation, with increased production of short-chain fatty acids and gases, which contribute to symptom generation.…”

Section: Introductionmentioning

confidence: 99%

Functional variants in the sucrase–isomaltase gene associate with increased risk of irritable bowel syndrome

Henström

Diekmann²,

Bonfiglio

et al. 2016

Gut

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Objective IBS is a common gut disorder of uncertain pathogenesis. Among other factors, genetics and certain foods are proposed to contribute. Congenital sucrase–isomaltase deficiency (CSID) is a rare genetic form of disaccharide malabsorption characterised by diarrhoea, abdominal pain and bloating, which are features common to IBS. We tested sucrase–isomaltase (SI) gene variants for their potential relevance in IBS. Design We sequenced SI exons in seven familial cases, and screened four CSID mutations (p.Val557Gly, p. Gly1073Asp, p.Arg1124Ter and p.Phe1745Cys) and a common SI coding polymorphism (p.Val15Phe) in a multicentre cohort of 1887 cases and controls. We studied the effect of the 15Val to 15Phe substitution on SI function in vitro. We analysed p.Val15Phe genotype in relation to IBS status, stool frequency and faecal microbiota composition in 250 individuals from the general population. Results CSID mutations were more common in patients than asymptomatic controls (p=0.074; OR=1.84) and Exome Aggregation Consortium reference sequenced individuals (p=0.020; OR=1.57). 15Phe was detected in 6/7 sequenced familial cases, and increased IBS risk in case–control and population-based cohorts, with best evidence for diarrhoea phenotypes (combined p=0.00012; OR=1.36). In the population-based sample, 15Phe allele dosage correlated with stool frequency (p=0.026) and Parabacteroides faecal microbiota abundance (p=0.0024). The SI protein with 15Phe exhibited 35% reduced enzymatic activity in vitro compared with 15Val (p<0.05). Conclusions SI gene variants coding for disaccharidases with defective or reduced enzymatic activity predispose to IBS. This may help the identification of individuals at risk, and contribute to personalising treatment options in a subset of patients.

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Maltase‐Glucoamylase Modulates Gluconeogenesis and Sucrase‐Isomaltase Dominates Starch Digestion Glucogenesis

Cited by 45 publications

References 25 publications

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Review: Nutritional regulation of intestinal starch and protein assimilation in ruminants

Gut feedback mechanisms and food intake: a physiological approach to slow carbohydrate bioavailability

Functional variants in the sucrase–isomaltase gene associate with increased risk of irritable bowel syndrome

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