A study on retinal photoisomerization catalyzed by a protein from the honeybee visual system

The photoisomerization of all-trans retinal catalyzed by an isomerase purified from the honeybee retina is stereospecifically directed toward the formation of 11-cis retinal, the isomer required for rhodopsin regeneration. A model of the enzymatic reactions was developed, which fits the experimental data. In a particular experiment where irradiation was performed with a LASER light, the rate constants of the photoisomerization of all-trans retinal were dependent on the light intensity and were therefore greatly enhanced.