Proteins are the most abundant biomolecules, constituting more than 50% of the dry weight of the cell. They are known to perform many different biological functions. Qualitative and quantitative estimation of proteins in biological fluids is based on the physico-chemical properties of proteins.
In each type of protein, the three dimensional structure is essential for its biological function. A protein in the biologically active form is termed as the native protein and the native state is called “optimum” state. The disruption of the three dimensional structure is called denaturation. On denaturation, the primary structure remains intact. It is an all or none phenomenon and does not cause any alteration in the quantity of protein present.
Following are the major changes involved in denaturation:
1. Increase in the viscosity due to uncoiling
2. Change in the isoelectric pH
3. Changes in the properties of solubilization and crystallization
4. Loss of biological activity.
(Read more at: http://edusanjalbiochemist.blogspot.com/2015/12/qualitative-and-qualitative-estimation.html)
|Fig. Test tube showing Biuret test positive|