Protein is a micronutrients which yields the amino acids upon hydrolysis.
Micronutrients : proteins, fats and Carbohydrates.

Properties of Protein :

• Molecular weight mixed polymer of a amino acids together with peptide linkage.
• Chain of amino acids joined by peptide bond in a specific sequence.
• Organic compound Contain C, H, O and P, S. Mixed polymer of amino acid.
• Joined together by peptide bond.
• These are found in animal products those always present in Sources, such as nuts and legumes.
• Fundamental basis of structures and function of life.
• 4 calories present in a each gram of protein.
• Proteins makes a weight 15% of human body. It is composed of amino acids.
• Amino acids are organic compounds made up of carbon, hydrogen, nitrogen, oxygen or sulfur.
• Proteins makes a weight 15% of human body.

Structure of Protein :

Depends upon the spatial arrangement of polypeptide chains.
There are three arrangements are possible.

Primary structure of Protein :

• Linear sequence of amino acids a peptide or protein.
• Primary structure starting with amino – acids terminal(N). And end with carboxy-terminal(C).
• With the help of DNA sequences protein structure can be directly sequenced or inferred.

Secondary structure of Protein :

• It is defined by peptide chains may acquire in spiral shape or may be present in zig-zag manner.
• Coiling of peptide chains is called the secondary structure of proteins.
• Secondary structure formed by hydrogen bonding.

Tertiary structure of Protein :

• It is the three dimensional structure of protein.
• Twisting and folding of polypeptide chains represents tertiary structure of protein.

Quaternary structure of Protein :

• It is the arrangements of multiple folded protein molecules in a multi-subunit complex.
• Variety of bonding interactions including hydrogen bonding, salts bridges and disulfide bonds. These bonds holds the various chain into a particular geometry.