Protein denaturation

1st method of denaturation - extreme temperature

1. Heating increases the kinetic energy, resulting in the increased vibration within the molecules. 2. Hydrogen bonds and VDW interactions that hold the secondary, tertiary and quarternary structures are broken. 3. At higher temperatures, ionic bonds between charged R groups and disulfide linkages may also be broken. 4. Most globular proteins denature at 60-70 degrees celsius.

3rd method of denaturation - adding heavy metals

1. Hg2+, Cu2+, Ag+ 2. Heavy metals will form salt/complex ions, breaking ionic interactions. 3. Disulphide bonds are also broken.

2nd method of denaturation - extreme pH changes

Adding acids/bases will protonate/deprotonate the ionic R groups, thereby destroying the ionic and hydrogen bonds in the protein.

4th method of denaturation

Addition of organic solvents

Denaturation

Involves destroying the forces that hold the protein together, disrupting their 3-dimensional shape, hence resulting in the unfolding of the protein and loss of their biological activity

However, the primary structure remains unaffected

The peptide bonds remains undisrupted and the chains of amino acids remain intact

5th method of denaturation - oxidizing and reducing agents

The redox reagents can either create or destroy the disulphide linkages in the protein.

Denaturation occurs when

The secondary, tertiary and quaternary structures or protein are destroyed