Cell-free biosynthesis of lipophosphoglycan from Leishmania donovani. Characterization of microsomal galactosyltransferase and mannosyltransferase activities
- Department of Biochemistry, University of Kentucky Medical Center, Lexington (USA)
Incubation of microsomal preparations from Leishmania donovani parasites with UDP-({sup 3}H)galactose or GDP-({sup 14}C)mannose resulted in incorporation of radiolabel into an endogenous product that exhibited the chemical and chromatographic characteristics of the parasite's major surface glycoconjugate, lipophosphoglycan. The ({sup 3}H)galactose- or ({sup 14}C)mannose-labeled product was (1) cleaved by phosphatidylinositol-specific phospholipase C; (2) deaminated by nitrous acid; and (3) degraded into radioactive, low molecular weight fragments upon hydrolysis with mild acid. Analysis of the products of mild acid hydrolysis revealed the presence of phosphorylated Gal-beta-Man as the major fragment with lesser amounts of mono-, tri-, and tetrasaccharides. The incorporation of the two isotopic precursors was neither stimulated by the addition of dolichylphosphate nor inhibited by amphomycin, indicating that dolichol-saccharide intermediates are not involved in assembly of the repeating units of lipophosphoglycan. Development of this cell-free glycosylating system will facilitate further studies on the pathway and enzymes involved in lipophosphoglycan biosynthesis.
- OSTI ID:
- 5398684
- Journal Information:
- Journal of Biological Chemistry; (United States), Journal Name: Journal of Biological Chemistry; (United States) Vol. 266:17; ISSN JBCHA; ISSN 0021-9258
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BIOSYNTHESIS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CELL CONSTITUENTS
CELL MEMBRANES
CHEMICAL COMPOSITION
CHROMATOGRAPHY
ENZYME ACTIVITY
ENZYMES
ESTERS
GALACTOSE
HEXOSES
HYDROGEN COMPOUNDS
INVERTEBRATES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIPIDS
MANNOSE
MEMBRANES
MICROORGANISMS
MICROSOMES
MOLECULAR WEIGHT
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PARASITES
PHOSPHOLIPIDS
PROTOZOA
RIBOSOMES
SACCHARIDES
SEPARATION PROCESSES
SYNTHESIS
TRACER TECHNIQUES
TRANSFERASES
TRITIUM COMPOUNDS