CLASSIFICATION OF PROTEINS BASED ON PHYSIOCHEMICAL PROPERTIES

Based on proteins' function, proteins may be classified as regulatory or hormonal proteins, structural proteins, transport proteins, genetic proteins and physiochemical proteins. But here, I am only going to define proteins based on physiochemical behavior. Based on physiochemical properties, proteins are classified into following types:

• Simple Proteins
• Compound or Conjugated Proteins
• Derived Proteins

Simple Proteins:

These proteins on hydrolysis yield only amino acids or occasional carbohydrates and their derivatives. For example, albumins, globulins, lefumin, collagen, etc. Globulins are insoluble in water but soluble in dilute salt solutions. They are found in animals, e.g. lactoglobulin is found in muscles and also in plants. Legumin and collagen proteins are present in the connective tissues throughout the body. They are the most abundant proteins in the animal kingdom forming some 25-35 percent of body protein.

Globulin 

Compound or Conjugated Proteins:

In these molecules the protein is attached or conjugated to some non-protein groups which are called prosthetic groups. For example, phospho-proteins are conjugated with phosphoric acid; lipoproteins are conjugated with lipid substances like lecithin, cholesterol and fatty acids.

Derived Proteins:

As the word “derived” is showing that this class of protein includes substances which are derived from simple and conjugated proteins. For example, proteoses enzymes, peptones, oligopeptides, polypeptides, etc.

Polypeptide chain