General Veterinary Biochemistry

CLASSIFICATION BASED ON THE SIDE CHAIN GROUP

• These are amino acids, having no functional groups attached to the aliphatic side chain. Eg: glycine, alanine, valine, leucine and isoleucine.
• The amino acid valine, leucine and isoleucine contain branched aliphatic side chains. Hence, they are also known as branched chain amino acids. 

Hydroxyl amino acids

• These are amino acids containing hydroxyl group in the side chain. Eg: serine and threonine.

Sulphur containing amino acids

• These are amino acids, containing a sulphur atom attached on the aliphatic side chain. Eg: cysteine, cystine and methionine. 

Acidic amino acids

• These amino acids will have one more carboxyl group attached on the side chain. Eg: aspartic acid and glutamic acid.

Basic amino acids

• These amino acids will have some nitrogen containing basic group attached on the side chain. Eg: lysine and arginine.

Aromatic amino acids

• These are amino acids containing the benzene nucleus attached on the side chain.
• Eg: phenylalanine, tyrosine and tryptophan. The nucleus present in tryptophan is known as indole. Presence of aromatic amino acids like tyrosine and tryptophan in protein, proteins absorb light at a wave length of 280nm

Heterocyclic amino acids

• These amino acids contain a ring, which is having one atom other than carbon atom. E.g.: histidine, proline and hydroxyproline.
• The proline and hydroxyproline are also called as imino acids, because they contain an imino group instead of an amino group, as found in other amino acids.

 

Aminoacid derivatives

• Amino acid derivatives are formed as an intermediate in the metabolic reactions.
• Eg: asparagine and glutamine derived from aspartic acid and glutamic acid respectively.