AMINOACID CHEMISTRY

​CHEMISTRY OF AMINO ACIDS
AND PROPERTIES OF AMINO ACID

​About 300 amino acids are present in the nature.
Only 20 are found in proteins - standard amino acids.

​Arginine Guanidine group

Phenylanine and tyrosine Benzene group

Tryptophan Indole group

Histidine imidazole group

proline and hydroxyline imino group

Multiple Choice

Which of the following amino acids is classified as a branched chain amino acid?

• Glycine

• Alanine

• Valine

• Serine

Multiple Choice

Which amino acid has a side chain consisting of only a hydrogen atom?

• Alanine

• Glycine

• Valine

• Leucine

Multiple Choice

Which of the following amino acids contains a hydroxyl group in its side chain?

• Serine

• Methionine

• Phenylalanine

• Lysine

Multiple Select

Select all amino acids that have an amide group in their side chain.

• Asparagine

• Glutamine

• Threonine

• Arginine

Multiple Choice

Which amino acid has an aromatic ring with a hydroxyl group attached?

• Tyrosine

• Phenylalanine

• Serine

• Methionine

Multiple Choice

Which of the following amino acids is classified as a heterocyclic amino acid?

• Tryptophan

• Alanine

• Serine

• Leucine

Multiple Choice

Which of the following amino acids have nonpolar (hydrophobic) side chains?

• Alanine

• Serine

• Aspartic Acid

• Glutamine

Multiple Choice

Which amino acid is classified as only ketogenic?

• Leucine

• Lysine

• Tyrosine

• Phenylalanine

Multiple Choice

Which of the following amino acids are found in collagen?

• Hydroxyproline

• Gamma carboxy glutamate

• Histidine

• Ornithine

Multiple Select

Which of the following are non protein α-amino acids?

• Ornithine

• DOPA

• β-Alanine

• Taurine

​PROPERTIES OF AMINO ACIDS

1. ​Physical property
   Solubility: most of the amino acids are soluble in water and insoluble in organic solvents
   
   2.Melting point: amino acid melt at higher temperature often above 200 degree celsius

   3.Amino acid may be sweet (Gyl, Ala, Val), Tasteless (Leu), bitter (Arg, Ile). Monosodium glutamate is a salt of glutamic acid

   it is employed as flavoring agent in food industry to increase the taste
   

Alpha carbon of each amino acid is attached to four different atoms/groups - asymmetric carbon atom. 

​ Amino acid- D and L

Open Ended

List any two examples of non protein non α-amino acids and mention their biological significance.

​•The mirror images  produced with reference to the alpha carbon atom (asymmetric carbon) , are called D and L isomers

•The L form occurs commonly in nature

•The D form occurs in some micro-organisms and  certain antibiotics.

•Amino group on right – D

•Amino group on left    – L

•

•which are mirror images of each other.

•These forms are known as    stereoisomer

•optical isomer – dextro & levorotatory

​Biuret reaction	​Peptide bond
​ninhydrin reaction	alpha amino acid​
​Xanthoproteic reaction	benzene ring​
​Millons reaction	Phenolic group​
Sakaguchi test ​	​Guanidino group (Arg)

​Colour reaction of proteins

Multiple Choice

Which amino acid is responsible for making hair curly?

• Cysteine

• Leucine

• Tryptophan

• Serotonin

Open Ended

What makes your hair curly, your muscles strong, and your brain work?