Digestion of carbohydrates Flashcards
Types of enzymes are important for the digestion
of carbohydrates
- Amylases
2. Disaccharidases
Disaccharidases function
Convert disaccharides to monosaccharides
Amylases function
convert polysaccharides to disaccharides
types of Amylases
- Salivary Amylase
2. Pancreatic Amylase
types of Disaccharidases
- Maltase
- Sucrase-Isomaltase
- Lactase
- Trehalase
Digestion of Carbohydrate starts in
the mouth
ptylin (salivary amylase) Location
mouth
ptylin (salivary amylase) optimum pHمهم
6.7 (Range 6.6 to 6.8)
ptylin (salivary amylase) action stops in
the stomach when the pH falls to 3.0.
ptylin (salivary amylase) structure and function
1.α-amylase and requires Cl− ion for activation
2.hydrolyses α-1→ 4 glycosidic linkages
for both amylase
Digestion in the Mouth Drawback
Shorter duration of food in mouth.
• Thus it is incomplete digestion of starch or
glycogen in the mouth.
Digestion in the Stomach
HCl causes hydrolysis of sucrose to fructose and glucose.
no enzyme to break the glycosidic bonds
Digestion in Duodenum
Pancreatic juice contains pancreatic amylase
amylopsin
pancreatic amylase Optimum pH
7.1
Only difference between salivary and pancreatic amylase
optimum pH
Salivary: 6.7
Pancreatic: 7.1
Starch/Glycogen Starch, and dextrins is converted by salivary amylase
Maltose and Maltotriose
Starch/Glycogen is converted by pancreatic amylase
Maltose/ Isomaltose +Dextrins and oligosaccharides
Main digestion takes place in
the small intestine by pancreatic amylase. Digestion is completed by pancreatic amylase because food stays for a longer time in the
intestine
Disaccharidases location
brush border epithelium of intestinal mucosal cells
Maltose
Glucose + Glucose
Sucrose Isomaltose
3Glucose + fructose
Lactose
Glucose + Galactose
Congenital Lactose intolerance
- complete deficiency of lactase enzyme.
- after birth.
- diagnosed in early infancy
- Milk feed precipitates symptoms
Primary Lactase deficiency
during adulthood.
2.gene >RNA → no enzyme
intolerance to milk + dairy products.