Avidin occurs in raw egg white. It is a glycoprotein which
combines stoichiometrically with biotin thereby preventing the
absorption of biotin across the intestinal mucosa. Avidin can
be used in research investigations designed to study the
function of biotin or in the study of enzyme systems where
biotin serves as a coenzyme. Berger and Wood have described
the application of avidin or avidin subunits, bound to a
matrix, in affinity chromatography (Berger, M. and Wood, H.S.,
J. Biol. Chem., 250, 927, 1975).
Avidin contains four polypeptide chains which are essentially
identical. It has a molecular weight of 68,000.