Avidin is a homotetrameric glycoprotein found in the egg white of birds, reptiles and amphibians. Each subunit is 16 kDa, singly glycosylated and binds to a molecule of biotin with greater affinity and specificity. Recombinant avidin from corn is similar to avidin from egg white in terms of properties like isoelectric point (pI) and antigenic properties except for the molecular weight. Avidin from corn has low molecular weight than chicken egg-derived avidin. This might be due to less complex glycosylation composition in plants. Commercial production of avidin from corn has certain advantages in terms of availability of greater biomass and avoiding the co-purification of animal virus.
Avidin forms an extremely strong complex with d-biotin (Kd ~ 10-15). This activity has made both avidin and biotin extremely useful labels in immunochemical methods of detection and quantitation.
5 mg in glass bottle
One unit will bind 1.0 μg of d-biotin.