Lysosomal processing of sialoglycoconjugates in a wheat germ agglutinin resistant variant of EL4 murine leukemia cells

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:6158577

Devino, N L

Metabolic studies were undertaken in EL4 murine leukemia in WB6, a wheat germ agglutinin-resistant variant of EL4, in order to identify any differences in lysosomal processing of sialoglyco-conjugates. Five lysosomal acid hydrolases, acetylesterase, acid phosphatase, {beta}-galactosidase, {alpha}-mannosidase, and neuraminidase, were studied using fluorescent 4-methylumbelliferyl substrates. No significant differences were found in the total activity of any of these enzymes in EL4 and WB6. Cells were incubated in the presence of N-acetylmannosamine, the metabolic precursor of sialic acid (N-acetylneuraminic acid). Free sialic acid accumulated in the lysosomes of WB6 but not of EL4. The accumulation of lysosomal free sialic acid in WB6 showed a dependence on the concentration of N-acetylmannosamine in the growth medium. Metabolic labelling with (6-{sup 3}H)-N-acetylmannosamine showed that WB6 accumulated lysosomal free sialic acid even at very low concentrations of N-acetylmannosamine. The two cell lines differed in their distribution of radiolabelled neutral sugars, free sialic acid, and sialoglycoproteins. The velocity of {sup 3}H-sialic acid release was 3.7-fold lower in WB6 than in EL4, suggesting that WB6 has a defect in lysosomal sialic acid transport. The metabolic consequences of this defect are examined, in light of other biochemical and immunological data on these cells.

• Research Organization: Florida State Univ., Tallahassee, FL (USA)
• OSTI ID: 6158577
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID PHOSPHATASE
AMINES
ANIMAL CELLS
CARBOHYDRATES
CELL CONSTITUENTS
DISEASES
ENZYME ACTIVITY
ENZYMES
ESTERASES
GALACTOSIDASE
GLUCOSIDASE
GLYCOSYL HYDROLASES
HEMIC DISEASES
HYDROGEN COMPOUNDS
HYDROLASES
IMMUNE SYSTEM DISEASES
ISOTOPE APPLICATIONS
LEUKEMIA
LYSOSOMES
METABOLISM
MONOSACCHARIDES
NEOPLASMS
O-GLYCOSYL HYDROLASES
ORGANIC COMPOUNDS
ORGANOIDS
PHOSPHATASES
SACCHARIDES
SIALIC ACID
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TUMOR CELLS