Biosynthesis of a mannolipid containing a metabolite of retinoic acid by 3T12 mouse fibroblasts
Retinol and retinoic acid (RA) increase the adhesive properties of spontaneously transformed mouse fibroblasts and the incorporation of (2-/sup 3/H)mannose into cellular glycoconjugates. Therefore we searched for a mannolipid of retinoic acid similar to mannosylretinylphosphate (MRP) in these cells. Labeled RA was incorporated into a compound similar to standard MRP. This metabolite contained the same /sup 3/H:/sup 14/C ratio as the precursor (11, 12-/sup 3/H, 15-/sup 14/C)retinoic acid, demonstrating that no decarboxylation had occurred. A doubly labeled mannolipid was obtained from cells incubated with (2-/sup 3/H)mannose and (15-/sup 14/C)retinoic acid. This mannolipid was readily cleaved by mild acid, yielding (/sup 3/H)mannosephosphate and a compound that migrated as standard anhydroretinol at Rf 0.93. Standard all trans-MRP yields all-trans-anhydroretinol under these conditions. A HPLC system was developed to further characterize the mannolipids obtained from retinol and retinoic acid in 3T12 cells. (15-/sup 3/H)Retinol and (15-/sup 14/C)retinoic acid were incorporated into mannolipids that cochromatographed with standard MRP. The mixture of the (15-/sup 3/H)retinol and (15-/sup 14/C)retinoic acid derived mannolipids was subjected to mild acid hydrolysis, after purification by HPLC yielding all-trans-(/sup 3/H)anhydroretinol and a (/sup 14/C)labeled product which was eluted from HPLC as a slightly more polar compound than all-trans-anhydroretinol. The retinoic acid-derived mannolipid (MXP) represented approximately 4% of the total radioactivity in the methanolic extract of 3T12 cells incubated in labeled retinoic acid. However, if the cells were incubated for an additional 20 hours in the absence of the radioactive precursor, MXP represented 40% of the total extracted radioactivity.
- OSTI ID:
- 5467242
- Journal Information:
- Ann. N.Y. Acad. Sci.; (United States), Journal Name: Ann. N.Y. Acad. Sci.; (United States) Vol. 359; ISSN ANYAA
- Country of Publication:
- United States
- Language:
- English
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550501 -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL CELLS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBOXYLIC ACID ESTERS
CONNECTIVE TISSUE CELLS
ESTERS
FIBROBLASTS
KINETICS
LABELLED COMPOUNDS
MAMMALS
METABOLISM
METABOLITES
MICE
ORGANIC COMPOUNDS
PRECURSOR
REACTION KINETICS
RETINOIC ACID
RODENTS
SOMATIC CELLS
SYNTHESIS
TRITIUM COMPOUNDS
VERTEBRATES
VITAMIN A
VITAMINS