Patent ID: 7205393

Claim:
A process for the isolation and purification of Avidin from egg white, the said process comprising steps of: a) homogenizing egg white with a buffer to form a homogenized solution, b) lyophilizing the homogenized solution of step (a) to obtain a solid egg white material, c) dissolving the solid egg white material in a buffer to form a solution, d) adding the solution of step (c) to an equilibrated cation exchanger and incubating for an hour at a temperature range of 20° to 30° C. to give a mixture, e) filtering the mixture of step (d) to obtain a filtrate and a matrix residue, f) washing the matrix residue of step (e) twice with a buffer to obtain washed matrix, g) adding 0.01 M of a dye in a buffer to the washed matrix of step (f) and equilibrating for an hour in an orbital shaker, the dye selected from the group consisting of 4′hydroxyazobenzene-2-carboxylic acid, 4′-hydroxyazobenzene-4-carboxylic acid and 4′-dimethylaminobenzene-2-carboxylic acid, h) removing a supernatant after performing the eqiulibration of step (g), i) adding acetic acid to the supernatant of step (h), to form a solution with a final concentration of acetic acid of 0.2 N, and j) dialysing the solution of step (i) until it is decolorised to obtain pure Avidin.