Avidin is homotetrameric protein (66 kDa) obtained from egg whites and binds strongly to biotin. It has four identical subunits of 16,400 Daltons each. It is an attractive adaptor protein, that is resistant to denaturation. This glycoprotein is present in avian, reptilian and amphibian egg white. The product is affinity purified egg white avidin (acitivity 10-15 units/mg protein) conjugated to alkaline phosphatase using a 0.2% glutaraldehyde method.
Avidin-biotin association has been utilized in immunoassays to detect the localization of antigens in tissues. The use of avidin-biotin immunoassay enhances the sensitivity of the technique and facilitates the detection of antigens in low quantities. Avidin is a fatty acid biosynthesis regulator. It participates in terminal cell differentiation by weakening the multiplication of cell without affecting the differentiation process.
