# Amino Acids

Hello Guys…!!

The very first thing you might get into your mind is, “What are amino acids?” There are many types of amino acids and each are different from the other. Amino acids are the essential building blocks of each cell in an organism. Here are few details, types of amino acids and their properties.

1. All proteins are biological polymers made up of amino acid molecules linked together to form a long chain.
2. Amino acids contain a basic -NH₂ group and acidic – COOH group.
3. 20 different amino acids are obtained by the hydrolysis of the protein, which differ in -R group.

Molecular Formula: By changing the R group in rth structural formula of amines we get different types of amines.

1. If R is acidic then the amino acid will be acidic.
2. If the R is basic group then the amino acid will be basic.
3. If the R is basic group then the amino acid will be basic.

$$R-\underset{H}{\mathop{\underset{|}{\mathop{\overset{N{{H}_{2}}}{\mathop{\overset{|}{\mathop{C}}\,}}\,}}\,}}\,-COOH$$

Zwitter ion:  Exists as a dipole ion in the dry solid state.

$$\underset{Zwitterion}{\mathop{R-\overset{N{{H}_{3}}^{+}}{\mathop{\overset{|}{\mathop{CH}}\,}}\,-CO{{O}^{-}}}}\,$$

Properties of a zwitter ion: In aqueous solution an equilibrium is established for Zwitter Ion with their conjugate acid and base.

$$\underset{acidicmedialowpH}{\mathop{{{H}_{3}}N\,\,\underset{R}{\mathop{\overset{C{{O}_{2}}H}{\mathop{+}}\,}}\,\,H}}\,\underset{neutralform}{\mathop{{{H}_{3}}N\,\,\underset{R}{\mathop{\overset{C{{O}_{2}}^{-}}{\mathop{+}}\,}}\,\,H}}\,\underset{basicmediahighpH}{\mathop{{{H}_{2}}N\,\,\underset{R}{\mathop{\overset{C{{O}_{2}}^{-}}{\mathop{+}}\,}}\,\,\,H}}\,$$.

The optimum pH at which the concentration of Zwitter Ion is at Maximum is called “Isoelectric Point”.

Preparation of Amino Acids:

1. By Ammonolysis of alpha-haloacid.

$$RC{{H}_{2}}COOH\xrightarrow[{{H}_{2}}O]{{{X}_{2}}/P}R-\underset{X}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-COOH$$

$$R-\underset{X}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-COOH\xrightarrow[Excess]{N{{H}_{3}}}\underset{(Zwitter\,\,Ion)}{\mathop{\underset{+}{\mathop{R-\underset{N{{H}_{3}}}{\mathop{\underset{|}{\mathop{CH}}\,}}\,-CO{{O}^{-}}}}\,}}\,$$

2. By Stecker’s Synthesis: