ASCORBIC ACID (VITAMIN C)
Chemistry of Vitamin C
It is water soluble and is easily destroyed by heat, alkali and
storage.
In the process of cooking, 70% of vitamin C is lost.
The structural formula of ascorbic acid closely resembles that of
carbohydrates
The strong reducing property of vitamin C depends on the
double-bonded (enediol) carbons.
Only L-ascorbic acid and dehydroascorbic acid have antiscorbutic
activity.
Biosynthesis of Ascorbic Acid in Animals
Most animals and plants can synthesize ascorbic acid from glucose.
Man, higher primates, guineapigs and bats are the only species which
cannot synthesize ascorbic acid (block in gulonolactone oxidase step).
Excretion of Ascorbic Acid
The vitamin is excreted in urine.
Since vitamin C is a strong reducing agent, the Benedict's test will be
positive in the urine sample after the vitamin administration.
Biochemical Functions of Vitamin C
Hydroxylation of proline:
o Ascorbic acid is necessary for the post-translational hydroxylation
of proline and lysine residues.
Chemistry of Vitamin C
It is water soluble and is easily destroyed by heat, alkali and
storage.
In the process of cooking, 70% of vitamin C is lost.
The structural formula of ascorbic acid closely resembles that of
carbohydrates
The strong reducing property of vitamin C depends on the
double-bonded (enediol) carbons.
Only L-ascorbic acid and dehydroascorbic acid have antiscorbutic
activity.
Biosynthesis of Ascorbic Acid in Animals
Most animals and plants can synthesize ascorbic acid from glucose.
Man, higher primates, guineapigs and bats are the only species which
cannot synthesize ascorbic acid (block in gulonolactone oxidase step).
Excretion of Ascorbic Acid
The vitamin is excreted in urine.
Since vitamin C is a strong reducing agent, the Benedict's test will be
positive in the urine sample after the vitamin administration.
Biochemical Functions of Vitamin C
Hydroxylation of proline:
o Ascorbic acid is necessary for the post-translational hydroxylation
of proline and lysine residues.
