Proteins are highly complex substance present in all living organisms. The term protein was first discovered by J. Berzelius. Proteins contain a complex nitrogen-rich organic substance bonded through peptide bonds and is made up of the molecules of carbon, hydrogen, oxygen and nitrogen. Along with this there are some proteins in which sulphur, zinc, phosphorus etc. are found in very small amounts. It nurtures the muscles within our body. The rich source of vital proteins is milk, egg, meat, fish, rice, cheese, pulses, nuts etc. There are mainly three types of proteins. Simple Protein, Conjugated Proteins and the Derived Proteins.
Simple proteins: Simple proteins are made up of only amino acids are called simple proteins like albumin, globumins, prolamins, gluremins etc. Hormones and enzymes are examples of simple and derived proteins.