Azurin is a metalloprotein in the family of cupredoxins. It preferentially enters cancer cells over normal cells and induces apoptosis. Azurin has structural similarities to ephrinB2, and in fact binds the ephrin receptor tyrosine kinase EphB2 to initiate cell signaling that is involved in cancer progression. Azurin inhibits autophosphorlyation of the EphB2 tyrosine residue, interfering with upstream cell signaling and contributing to cancer cell growth inhibition.
Azurin with A625/280 = 0.56 is purified by gel chromatography on G-25 Sephadex with 5mM phosphate pH 7 buffer as eluent [Cho et al. J Phys Chem 91 3690 1987]. It is a blue Cu protein used in biological electron transport, and its reduced form is obtained by adding a slight excess of Na2S2O4. [See Structure and Bonding Springer Verlag, Berlin 23 1 1975.]
