Affinity labeling of the galactose/N-acetylgalactosamine-specific receptor of rat hepatocytes: preferential labeling of one of the subunits

Journal Article · Tue Oct 06 04:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00394a005· OSTI ID:5562321

Lee, R T; Lee, Y C

The galactose/N-acetylgalactosamine-specific receptor (also known as asialoglycoprotein receptor) of rat hepatocytes consists of three subunits, one of which (43 kilodalton (kDa)) exists in a greater abundance (up to 70% of total protein) over the two minor species (52 and 60 kDa). When the receptor on the hepatocyte membranes was photoaffinity labeled with an /sup 125/I-labeled high-affinity reagent the labeling occurred mainly (51-80%) on one of the minor bands (52 kDa). Similarly, affinity-bound, N-acetylgalactosamine-modified lactoperoxidase radioiodinated the same 52-kDa band preferentially. In contrast, both the photoaffinity labeling and lactoperoxidase-catalyzed iodination of the purified, detergent-solubilized receptor resulted in a distribution of the label that is comparable to the Coomassie blue staining pattern of the three bands; i.e., the 43-kDa band was the major band labeled. These and other experimental results suggest that the preferential labeling of the minor band and inefficient labeling of the major band on the hepatocyte membrane resulted from a specific topological arrangement of these subunits on the membranes. The authors postulate that in the native, membrane-bound state of the receptor, the 52-kDa minor band is topologically prominent, while the major (43 kDa) band is partially masked. This partial masking may result from a tight packing of the receptor subunits on the membranes to form a lattice work.

• Research Organization: Johns Hopkins Univ., Baltimore, MD
• OSTI ID: 5562321
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:20; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
CARBOHYDRATES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
GLUCOPROTEINS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LABELLING
LIVER CELLS
MAMMALS
MEMBRANE PROTEINS
MOLECULAR STRUCTURE
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SACCHARIDES
SOMATIC CELLS
VERTEBRATES