Isolation by polyacrylamide gel electrophoresis of a light-sensitive vitamin A-protein complex from the retina of the honeybee drone

Polyacrylamide gel electrophoresis was performed on retinal homogenates from honeybee drones previously treated with tritiated vitamin A. After a 6-hr exposure to tritiated vitamin A in vivo or a 1-hr exposure in vitro, radioactivity appears as a single band in the gel of Davis and Ornstein for soluble proteins. No radioactivity is recovered in the SDS gel of Weber and Osborn for insoluble proteins. When labeled retinal homogenates are irradiated with white light, the radioactivity recovered in the gel of Davis and Ornstein diminishes proportionally with the time of illumination. In the presence of hydroxylamine, illumination removes all radioactivity from the protein band. Conversely, sodium borohydride added to the labeled homogenates prevents the radioactivity to be removed by illumination. These results indicate that the drone retina contains a soluble, photosensitive vitamin A-protein complex, which may represent a precursor of the visual pigment in the eye.