Proteins are unbranched polymers constructed from 22 standard α-amino acids.
The protein show four levels of structural organisation; the primary structure, secondary structure, tertiary structure and quaternary structure.
The structure of proteins are stabilized by peptide bonds between the amino acid and hydrogen bond between the peptide chainds.
The primary structure of a protein is determined by the sequence of amino acids, but secondary and tertiary structures of protein define their natural or native conformation.
The solubility of protein varies according to the pH, ionic strength, nature of solvent, temperature etc.
Proteins can be classified as simple proteins or conjugated proteins on the basis of their composition.
The proteins can also be classified as fibrous proteins or globular proteins on the basis of their shape.
Proteins play a major part in body structure and function as most of the molecules like antibodies, immunoglobulins, hemoglobin, myoglobin ,most of the enzymes are proteins.
So proteins are also called building blocks of the body.
