Persistence of species variation and regional heterogeneity of the apparent molecular masses of benzodiazepine-binding proteins after deglycosylation

• Published in: FEBS letters 1988-09, Vol.237 (1), p.199-202
• Main Authors: Schmitz, Elke, Friedl, Waltraut, Reichelt, Ralf, Hebebrand, Johannes
• Format: Article
• Language: English
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Birds; brain; Cattle; Deglycosylation; Ducks; Fishes; Flunitrazepam - metabolism; Fundamental and applied biological sciences. Psychology; GABA/benzodiazepine receptor; Genetic Variation; Glycoside Hydrolases; Glycosylation; Isoreceptor; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; Miscellaneous; Photoaffinity labeling; Proteins; Receptors, GABA-A - genetics; Receptors, GABA-A - isolation & purification; Receptors, GABA-A - metabolism; Species Specificity; Species variation; Swine; Vertebrata
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(88)80201-1

Brain membrane preparations of different vertebrates were photoaffinity labeled with [ 3H]flunitrazepam and subsequently deglycosylated with endoglycosidase F and peptide N-glycopeptidase. SDS-polyacrylamide gel electrophoresis followed by fluorography revealed that each benzodiazepine-binding protein is deglycosylated in two steps, indicating that each protein has two glycosylation sites. Species variation of the apparent molecular masses of the benzodiazepine-binding proteins and regional heterogeneity in avians persist after deglycosylation. These results indicate that the α-subunit(s) of the GABA/benzodiazepine receptor has undergone electrophoretically detectable changes in its amino acid composition during vertebrate evolution. The existence of at least two different α-subunits in avians is further substantiated.