The tryptic and chymotryptic fragments of the beta-subunit of guanine nucleotide binding proteins in brain are identical to those of retinal transducin.
The 35-kDa beta-subunit of transducin purified from rod outer segment membranes is cleaved into 2 major fragments by trypsin, and 7 major fragments by chymotrypsin. Identical fragments are visualized by immunoblotting with transducin-beta specific antisera after proteolysis of rod outer segment membranes, purified brain guanine nucleotide binding proteins, and brain membranes. The results indicate that the beta-subunits of transducin and of brain guanine nucleotide binding proteins are not only similar structurally, but are also similarly oriented in membranes with respect to accessibility to proteolytic enzymes.
D000818:Animals; D001923:Brain Chemistry; D002918:Chymotrypsin / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000378:metabolism; D007158:Immunologic Techniques; D008565:Membrane Proteins / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D010786:Photoreceptor Cells / Q000032:analysis*; D012374:Rod Cell Outer Segment / Q000032:analysis*; D015293:Transducin; D014357:Trypsin / Q000378:metabolism
D008565:Membrane Proteins; D010446:Peptide Fragments; D002918:Chymotrypsin; D014357:Trypsin; D019204:GTP-Binding Proteins; D015293:Transducin