Amino Acid
(Short Note)
Definition
Amino Acids are the common compounds
which contain both carboxylic and amino group.
Carboxylic group is acidic whereas,
the amino group is basic.
General
Formula
The general formula of amino acid is
R-CNH2H-COOH
Where,
R = alkyl Group
NH2 = Amino Group
COOH = Carboxylic Group
These amino acids are also called α –
amino acids because the amino groups is present on α – carbon atom to the
carboxylic group.
Classification of Amino Acids
On the basis of number of carboxylic
group (-COOH) and amino group (-NH2). Amino acids are classified into the
following three classes.
1. Neutral Amino Acids
2. Acidic Amino Acids
3. Basic Amino Acids
1. Neutral Amino Acids
Those amino acids, which have equal
number of -COOH and -NH2 groups, are called Neutral Amino Acids.
Example
1. Glycine (CH2NH2COOH)
2. Alanine (CH3-CH-NH2-COOH)
2. Acidic Amino Acids
Those amino acids, which have greater
number of -COOH than -NH2 groups are called Acidic Amino Acids.
Example
1. Asparite [CH2NH2CH(COOH)2]
2. Glutamic
[HOOC-CH2-CH2-CH-NH2-COOH]
3. Basic Amino Acids
Those amino acids, which cotain
greater number of -NH3 than -COOH groups, are called Basic Amino Acids.
Example
1. Lysine [H2N-(CH2)4-CH-NH2-COOH]
Zwitter Ion
When the hydrogen ion of carboxylic
group is accepted by amino group in amino acid then Zwitter ion is formed.
Zwitter ion is a German word, its
meaning is two charged ion, i.e. both positive and negative charge. This ion is
electrically neutral. In solution amino acid, exist in following ionic form.
Peptide Bond Or Peptide Linkage
In the polymers of amino acids,
different amino acids are linked together through a bond or linkage, which is
known as peptide bond or Peptide bond or Peptide Linkage.
When the hydrogen of amino acid
combine with the OH group of other amino acid to form water, the bond between
Nitrogen of one amino acid and carbon of other amino acid is formed which is
known as Peptide Bond or Linkage. This peptide bond is formed in proteins which
are the polymers of amino acids.
Diagram Coming Soon
Essential Amino Acids
Naturally occuring amino acids are known
as, essential amino acids.
A large number of sunthetic amino
acids are known, but only 20 amino acids occur in nature.
Properties of Amino Acids
The properties of amino acids are as
follows.
1. Amino acids are soluble in water,
but insoluble in organic solvents.
2. Amino acids are solids.
3. Amino acids have high melting
point.
4. They donate or accept proton in
the medium in which they are dissolved.
Function of Amino Acids
The role of amino acids in the human
body is as follows.
1. Amino Acids can be synthesized
back into Proteins.
2. Amino Acids oxidize to provide
energy.
3. Amino Acids may be transformed
into carbon hydrates or fats.
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