Studies on the mechanism of the enzymatic photoisomerization of retinal

Isidoro Mario Pepe and Carlo Cugnoli

Institute of Biophysics, Faculty of Medicine, University of Genoa and Institute of Cybernetics and Biophysics of C.N.R., Genoa, Italy


The honeybee retina contains the enzyme photoisomerase which converts all-trans retinal to 11-cis retinal in the light of visual range. The activity of the bee photoisomerase was studied on all-trans retinal under pulses of a laser light. The experimental data was fitted with a simple equation, which describes the mechanism of the isomerization reaction based on three steps having different time constants.

Keywords: Retinal isomerase; Vision; Photoisomerase; Honeybee retina