Enzymic construction of maltosaccharide chains on a heart protein

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6078988

Kay, M J; Kirkman, B R; Lomako, J; Rodriguez, I R; Tandecarz, J S; Fliesler, S J; Whelan, W J

The authors have reported that when 100,000 g pellets of rabbit-heart and rabbit-muscle homogenates are incubated with UDP(/sup 14/C)glucose, the sugar is incorporated into a protein with Mr 40 KDa. They suggested that these in vitro observations corresponded to the initial stage in the synthesis of glycogen on a protein that they have named glycogenin and which in rabbit muscle appears to be covalently linked to the glycogen via tyrosine residues. The following new observations support the role of a protein as the precursor of glycogen and suggest that glycogen-free glycogenin is present in heart tissue. (1) The (/sup 14/C)glucose residues added to the heart protein can be removed with glycogenolytic enzymes that hydrolyse 1,4-alpha-glucosidic bonds and therefore constitute synthetic maltosaccharide chains. (2) The newly added glucose residues appear to be attached to pre-existing glucose residues on the protein. Chain elongation does not proceed beyond a few glucose residues. (3) The further relevance of these observations to glycogen synthesis shown by a Western blot in which the radioglucosylated heart protein was found to cross-react with polyclonal antibody to glycogenin obtained from rabbit-muscle glycogen.

• Research Organization: Univ. of Miami School of Medicine, FL
• OSTI ID: 6078988
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARDIOVASCULAR SYSTEM
ENZYMES
GLUCOPROTEINS
GLUCOSE
HEART
HEXOSES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MOLECULAR STRUCTURE
MONOSACCHARIDES
MUSCLES
ORGANIC COMPOUNDS
ORGANS
PRECURSOR
PROTEINS
RABBITS
SACCHARIDES
TRACER TECHNIQUES
VERTEBRATES