Ref ID : 3804
Harold B. Skrdlant and Robert A. Weisman; Glucolipid Synthesis in Acanthamoeba castellanii. J.Protozool. 23(4):613-618, 1976
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Cell-free preparations of Acanthamoeba castellanii trophozoites transfer glucose from UDP-[U-14C]glucose to a chloroform-soluble form. This radioactive material has been isolated by thin-layer chromatography; it contains an alkali-labile and an alkali-stable (unsaponifiable) component. Treatment of the enzymic product with 0.1N KOH for 15 min at 0 C or 20 C releases radioactivity into the aqueous phase as glucose. During this treatment, 30-60% of the original glycolipid remains chloroform-soluble. It is considered to be an alkali-stable glycolipid because no further loss of radioactivity occurs during an additional 45-min of treatment with 0.1N KOH. During incubation with 0.1N HCl at 100 C glucose is released quantitatively from both the untreated glycolipid and the alkali-stable glycolipid with a half-time of 6 min. Glycolipid formation is inhibited by UDP and is reversible; extracts catalyze the formation of UDP-glucose from the alkali-stable glucolipid and UDP. The chemical and physical properties of the alkali-stable glycolipid are consistent with a glucosyl phosphoryl polyprenol structure. Extracts prepared from cysts catalyze the formation of glycolipids also, but the glucosyltransferase activity/cell decreases during the course of encystment. Radioactivity is incorporated into the fraction insoluble in chloroform-methanol-water (1:1:1) during these incubations when UDP-[U-14C]glucose or [14C]glycolipid is the substrate.