Rates of processing of the high mannose oligosaccharide units at the three glycosylation sites of mouse thyrotropin and the two sites of free alpha-subunits

Journal Article · Thu Sep 01 04:00:00 EDT 1988 · Endocrinology; (United States)

OSTI ID:6772251

Miura, Y; Perkel, V S; Magner, J A

We have determined the structures of high mannose (Man) oligosaccharide units at individual glycosylation sites of mouse TSH. Mouse thyrotropic tumor tissue was incubated with D-(2-/sup 3/H)Man with or without (/sup 14/C)tyrosine ((/sup 14/C) Tyr) for 2, 3, or 6 h, and for a 3-h pulse followed by a 2-h chase. TSH heterodimers or free alpha-subunits were obtained from homogenates using specific antisera. After reduction and alkylation, subunits were treated with trypsin. The tryptic fragments were then loaded on a reverse phase HPLC column to separate tryptic fragments bearing labeled oligosaccharides. The N-linked oligosaccharides were released with endoglycosidase-H and analyzed by paper chromatography. Man9GlcNac2 and Man8GlcNac2 units predominated at each time point and at each specific glycosylation site, but the processing of high Man oligosaccharides differed at each glycosylation site. The processing at Asn23 of TSH beta-subunits was slower than that at Asn56 or Asn82 of alpha-subunits. The processing at Asn82 was slightly faster than that at Asn56 for both alpha-subunits of TSH heterodimers and free alpha-subunits. The present study demonstrates that the early processing of oligosaccharides differs at the individual glycosylation sites of TSH and free alpha-subunits, perhaps because of local conformational differences.

• Research Organization: Univ. of Chicago, IL (USA)
• OSTI ID: 6772251
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 123:3; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINO ACID SEQUENCE
AMINO ACIDS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHROMATOGRAPHY
ENDOCRINE GLANDS
GLANDS
HEXOSES
HYDROXY ACIDS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LIQUID COLUMN CHROMATOGRAPHY
MAMMALS
MANNOSE
METABOLISM
MICE
MOLECULAR STRUCTURE
MONOSACCHARIDES
OLIGOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
REACTION KINETICS
RODENTS
SACCHARIDES
SEPARATION PROCESSES
THYROID
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TYROSINE
VERTEBRATES