Disaccharides
DISACCHARIDES
Summary
COMMON DISACCHARIDES
- Commonly dietary
- Made of 2 monosaccharides joined by O-glycosidic bond
- Formed by condensation reaction between –OH groups
- General formula: C12H22O11
Sucrose
- Glucose + fructose
- alpha-1,2-glycosidic bond: C1 –OH (alpha-D-glucose) + C2 –OH (beta-D-fructose)
- Common table sugar
- Sucrase: cleaves sucrose into monosaccharides
Maltose
- Glucose + glucose
- Alpha-1,4-glycosidic bond: C1 –OH (alpha-D-glucose) + C4 –OH (alpha-D-glucose)
- Product of starch/glycogen/large oligosaccharide hydrolysis
- Maltase: cleaves maltose into monosaccharides
Lactose
- Galactose + glucose
- Beta-1,4-glycosidic bond: C1 –OH (beta-D-galactose) + C4 –OH (alpha-D-glucose)
- Disaccharide in milk
- Lactase (humans)/beta-galactosidase (bacteria): hydrolyze lactase into monosaccharides