Disaccharides - Structureprofkatz.com/courses/wp-content/uploads/2013/05/Disaccharides-copy.pdf ·...
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Disaccharides - Structure The structures of the common dietary disaccharides can be partially deduced from their chemical and physical properties. Maltose - malt sugar (C 12 H 22 O 11 ) From partial hydrolysis of starch A reducing sugar Maltose HYDROLYSIS D-glucose + D-glucose Lactose - milk sugar (C 12 H 22 O 11 ) Found in milk A reducing sugar Lactose HYDROLYSIS D-galactose + D-glucose
Transcript of Disaccharides - Structureprofkatz.com/courses/wp-content/uploads/2013/05/Disaccharides-copy.pdf ·...
Disaccharides - StructureThe structures of the common dietary disaccharides can be
partially deduced from their chemical and physical properties.
Maltose - malt sugar (C12H22O11)From partial hydrolysis of starch
A reducing sugar
Maltose
HYDROLYSIS
D-glucose + D-glucose
Lactose - milk sugar (C12H22O11)Found in milk
A reducing sugar
Lactose
HYDROLYSIS
D-galactose + D-glucose
Disaccharides - Structure
Sucrose - table sugar (C12H22O11)Found in sugar cane and beets
NOT a reducing sugar
Sucrose
HYDROLYSIS
D-glucose + D-fructose
Disaccharides - Formed by Condensation
O
OH
OH
HO
HO
CH2OH
O
OH
OH
HO
HO
CH2OH
O
OH
HO
HO
CH2OH
O
OH
OH
HO
CH2OH
O
C6H12O6 + C6H12O6 ---------> C12H22O11 + H2O
+
Disaccharides - Structure of Maltose
Disaccharides - Structure of Lactose
Disaccharides - Why are Maltose and Lactose Reducing Sugars ?
Disaccharides - Structure of Sucrose
β
NOT areducingsugar !
Disaccharides - Structure
Disaccharides - Structure
Disaccharides - Structure
Disaccharides - Structure
Disaccharides - Digestion and Absorption
1) The sugars maltose (from starch digestion), lactose, and sucrose cannot be directly absorbed from the intestinal track.
2) Each must first be enzymatically hydrolyzed to the constituent monosaccharides:
Maltose ------------> glucose + glucose
Lactose -------------> glucose + galactose
Sucrose -------------> glucose + fructose
Enzymes are usually named by adding the suffix –ase to the name of the compound undergoing the reaction.
maltase
lactase
sucrase
Disaccharides - Lactose Intolerance
Causes of Galactosemia
Galactose
Glucose
Causes of Galactosemia
GalactoseGalactokinase
Consequences of Galactosemia
