Denaturation of Proteins

Denaturation refers to the breaking of weak bonds holding the secondary,tertiary and quartenary structure but not the covalent bonds within the primary structure

5 ways to denature proteins: Heating
pH changes
Mechanical agitation
add metal ions
add 8mol/dm^3 of urea

Heating:

Most globular proteins undergo denaturation when heated above 60 degree celcius

Effect: Disrupt the weaker Van der Waal's forces and hydrogen bonding to a lesser extent

Irreversible at high heat

Coagulation of egg white on heating

pH changes:

Protonates or deprotonates the ionic R groups, thus disrupting the electrostatic attractions involved in securing the tertiary and quarternary structure in place.

irreversible at extreme pH changes

coagulation of sour milk

Add metal ions

Disrupts the electrostatic attraction between the charged R groups of the amino acids by forming similar bonds with these groups.

Disrupt the formation of disulphide S-S bridges by forming bonds with -SH group of cysteine residue.

making of salted eggs by adding sodium chloride

Add urea:

Urea acts by competing for the intra molecular hydrogen bnds that stabilizes the structure

Reversible denaturation.