Persistence of species variation and regional heterogeneity of the apparent molecular masses of benzodiazepine-binding proteins after deglycosylation.
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 alpha-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 alpha-subunits in avians is further substantiated.
Schmitz
E
E
Institut für Humangenetik, Universität Bonn, FRG.
Friedl
W
W
Reichelt
R
R
Hebebrand
J
J
D000818:Animals; D001717:Birds; D002417:Cattle; D004372:Ducks; D005399:Fishes; D005445:Flunitrazepam / Q000378:metabolism; D014644:Genetic Variation; D006026:Glycoside Hydrolases; D006031:Glycosylation; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D011963:Receptors, GABA-A / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D013045:Species Specificity; D013552:Swine
D011963:Receptors, GABA-A; D005445:Flunitrazepam; D006026:Glycoside Hydrolases; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase