Carbohydrate Digestion Flashcards
Sites of Carbohydrate Digestion
Mouth and small intestine
Carbohydrate Dietary Sources
Starch, lactose, sucrose, trehalose, cellulose
2 Types of Digestion in Mouth
Mechanical (chewing) and Chemical (salivary amylase)
Salivary Amylase Action
Starch hydrolysed to maltose and dextrin. PH = 6.8- 7. Breaks down 5% of starch digestion
Pancreatic Enzymes for Carbohydrates
Alpha - amylase
Brush Border Enzymes for Carbohydrates
Disaccharidases, oligosaccharides, isomaltase and alpha (1,6) glucosidase
Alpha amylase
Endoglycosidase (attacks glycosidic bonds between internal C’s). Specific to 1,4 linkages (not 1, 6). Hydrolytic products: maltose, maltotirose and alpha limit dextrins
Maltase substrate and product
Substrate: maltose and maltotirose. Product: 2 glucose molecules
Sucrase substrate and products
Substrate: Sucrose. Product: glucose and fructose
Lactase substrate and product
Substrate: lactose. Products: glucose and galactose
Trehalase substrate and product
Substrate: Trehalsose. Products: 2 glucose molecules
Alpha amylase substrate
Polysaccarides
Disaccharidases Substrate
Disaccharides
Isomaltase Substrate
Branch points of oligosaccharides and dissacharides
Alpha (1,6) glucosidase
Branch points of oligosaccharides and dissacharides
Absorption into eneterocytes
Passive diffusion (very slow). Membrane associated transporters Na+ independent transporter (glut5, primary active) and Na+ co transporter transporter (SGGLUT1, secondary active)
Glut 1 Transporter Outline
Facilitated diffusion of glucose in and out of cell
Glut 2 Transporter Outline
Facilitated Diffusion. Glucose, galactose and fructose out of cell
Glut 5 transporter outline
Fructose into cell by facilitated diffusion
SGLT1 Transporter Outline
Active transport Na, glucose and galactose
