Avidin from chicken egg whites is a glycoprotein that effectively binds biotin, a tag that is frequently used to tag antibodies and other probes for immunodetection methods. Pure avidin is a key component in certain immunohistochemistry (IHC) methods. Alkaline phosphatase (AP) and horseradish peroxidase (HRP) conjugates of avidin are useful for Western blotting or ELISA detection with appropriate enzyme substrates. Avidin is a glycoprotein found in the egg white and tissues of birds, reptiles and amphibia. This protein contains four identical subunits having a combined molecular mass of 67,000 to 68,000 daltons. Each subunit binds one molecule of biotin, and studies have shown that tryptophan and lysine are involved in the binding site for biotin. The sequencing of the subunit indicates it consists of 128 amino acids. Avidin has an isoelectric point of 10-10.5 and is very soluble in water and salt solutions. Avidin is stable over a wide range of pH values and temperatures. Extensive chemical modification has little effect on the activity of avidin, making it useful for detection and protein purification. Avidin is sold by protein content (E1% at 280 nm). Definition of Activity:(/b> One Unit will bind 1 μg of D-biotin. Avidin conjugates also available: avidin-FITC ; avidin-PE ; avidin-APC ; avidin-PE-Cy7 ; avidin-APC-Cy7 .
应用:Frequently used to tag antibodies and other probes for immunodetection methods