Biosynthesis of ascites sialoglycoprotein-1, the major O-linked glycoprotein of 13762 rat mammary adenocarcinoma ascites cells
The present studies were undertaken to determine the timing of the major events in biosynthesis, and to characterize the contributions of chain initiation and elongation in maturation of the glycoprotein. Initiation of the earliest O-linked chains was detected by analysis of conversion of {sup 3}H-thr to {sup 3}H 2-aminobutyrate following mild alkaline borohydride elimination of O-linked sugars from peanut lectin-precipitated ASGP-1. Initiation was detected within 5 min of translation; amino sugar analysis of GlcNH{sub 2}-labeled, trypsinized cells also showed that GalNAc was added as late as 5 min prior to arrival of ASGP-1 at the cell surface. Thus initiation occurs throughout biosynthesis. Maturation of the glycoprotein from a lightly-glycosylated immature form to the heavily-glycosylated mature from involved both continued initiation of new chains and chain elongation, and occurred with a half-time of about 30 min. Analysis of labeled ASGP-1 released from the cell surface by trypsinization showed that although some newly-synthesized ASGP-1 reached the cell surface within 70-80 min of protein synthesis, the half-time for appearance of mature glycoprotein was in excess of 4 hr, indicating that most molecules reside in an intracellular compartment(s) for a considerable time.
- Research Organization:
- Miami Univ., Coral Gables, FL (USA)
- OSTI ID:
- 5564170
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GLYCOPROTEINS
BIOSYNTHESIS
MAMMARY GLANDS
CARCINOMAS
ASCITES TUMOR CELLS
BUTYRIC ACID
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ANIMAL CELLS
ANIMALS
BODY
CARBOXYLIC ACIDS
DISEASES
GLANDS
HYDROGEN COMPOUNDS
ISOTOPE APPLICATIONS
MAMMALS
MONOCARBOXYLIC ACIDS
NEOPLASMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PROTEINS
RODENTS
SYNTHESIS
TUMOR CELLS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550901 - Pathology- Tracer Techniques