Analysis of the oligosaccharide chains of rhodopsin from normal rats and those with hereditary retinal dystrophy

The nature of the oligosaccharides of rhodopsin from normal rats and from the Royal College of Surgeons (RCS) rats was examined by chemical, enzymatic and chromatographic procedures. This report is the first description of the structures of oligosaccharides of rat rhodopsin. The major oligosaccharide isomer of rat rhodopsin was shown to have the same structure as that from cow, human and frog. No neutral galactosylated species were detected. Although the site of the dystrophy in the RCS rat has been shown to be located at the retinal pigment epithelium, the possibility was examined that alterations in the glycosylation of rhodopsin might also be present. No differences were observed in either the amounts or structures of the rhodopsin oligosaccharide chains from young or adult control rats and RCS rats, although some differences were observed in the relative distribution of some oligosaccharide isomers between the RCS and controls. In addition, no differences in the amino acid content or SDS-PAGE patterns were detected.