title: Kinetic study of photochemical and thermal conversion of bilirubin IX alpha and its photoproducts.
abstract: A kinetic study of the photochemical and thermal conversion of photoisomers, especialy peaks 0 and 3 [(EE)-bilirubin IX alpha and (EZ)- and (ZE)-bilirubin IX alpha], under anaerobic conditions, was performed by using reversed-phase high-pressure liquid chromatography. Peaks 0 and 3 are spontaneously, photochemically and thermally converted. Short-term photoirradiation of bilirubin gives a mixture containing not only the geometric isomers (EE)-, (EZ)- and (ZE)-bilirubin IX alpha, but also peak 2, (EZ)-cyclobilirubin IX alpha. On prolonged irradiation, cyclization and 15Z leads to 15E isomerization lead to gradual accumulation of two pairs of photoproducts: (EZ)-cyclobilirubin IX alpha A and B and (EE)-cyclobilirubin IX alpha A and B.
mesh_terms: D001663:Bilirubin; D002851:Chromatography, High Pressure Liquid; D006358:Hot Temperature; D007536:Isomerism; D007700:Kinetics; D008956:Models, Chemical; D010777:Photochemistry
chemical_list: C028529:photobilirubin; D001663:Bilirubin