Urocanic acid photobiology. Photochemical binding of urocanic acid to bovine serum albumin

Abstract— The photolysis of E-[ring-2-¹⁴C]urocanic acid with bovine serum albumin (BSA) leads to incorporation of radiolabel into the protein. Levels up to 68 nmol mg^?1 BSA have been observed if the irradiation is carried out in an inert atmosphere. Oxygen reduces the level slightly. It appears from gel-filtration chromatography that the label incorporation is covalent in nature.