title: Site-specific and complete enzymic deglycosylation of the native human chorionic gonadotropin alpha-subunit.
abstract: Numerous studies have shown that glycosylation of the alpha-subunit of human chorionic gonadotropin (alpha hCG) is essential for the biological activity of this hormone. To obtain detailed insight into the function of N-glycosylation, the availability of site-specifically and fully deglycosylated alpha-subunits obtained under non-denaturing conditions is a prerequisite. NMR spectroscopy in combination with FAB-mapping demonstrates that only Asn52 of the alpha-subunit is accessible to digestion by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F under native conditions. Treatment of native alpha hCG with endo-beta-N-acetylglucosaminidase B results in full deglycosylation yielding alpha hCG with one GlcNAc residue at both Asn52 and Asn78.
authors.affiliation: Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
authors.forename: C W
authors.initials: CW
authors.lastname: Van Zuylen
authors.forename: T
authors.initials: T
authors.lastname: De Beer
authors.forename: G J
authors.initials: GJ
authors.lastname: Rademaker
authors.forename: J
authors.initials: J
authors.lastname: Haverkamp
authors.forename: J E
authors.initials: JE
authors.lastname: Thomas-Oates
authors.forename: K
authors.initials: K
authors.lastname: Hård
authors.forename: J P
authors.initials: JP
authors.lastname: Kamerling
authors.forename: J F
authors.initials: JF
authors.lastname: Vliegenthart
mesh_terms: D000581:Amidohydrolases / Q000378:metabolism; D000595:Amino Acid Sequence; D002240:Carbohydrate Sequence; D015292:Glycoprotein Hormones, alpha Subunit / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D015292:Glycoprotein Hormones, alpha Subunit; D000581:Amidohydrolases; D043524:Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase