Cellulose synthesis by extracts of Acanthamoeba castellanii during encystment. Stimulation of the incorporation of radioactivity from UDP-(14C)glucose into alkali-soluble and insoluble beta-glucans by glucose 6-phosphate and related compounds.
1. The activity of a particulate enzyme prepared from encysting cells of Acanthamoeba castellanii (Neff), previously shown to catalyze the incorporation of glucose from UDP-[14C]glucose into both alkali-soluble and alkali-insoluble beta-(1 leads to 4) glucans, was stimulated several fold by glucose-6-phosphate and several related compounds. 2. Incorporation was observed when [14C]glucose-6-P was incubated with the particles in the presence of UDP-glucose. The results of product analysis by partial acid hydrolysis indicated that glucose-6-P stimulates the formation of both alkali-soluble and alkali-insoluble beta-(1 leads to 4) glucans from UDP-[14C]glucose and was itself incorporated into an alkali-insoluble beta-(1 leads to 4)glucan. 3. When particles incubated with UDP-[14C]glucose and glucose-6-P were reisolated and then reincubated with unlabeled UDP-glucose and glucose-6-P, a loss of counts from the alkali-soluble fraction was detected along with a corresponding rise in the radioactivity of the alkali-insoluble fraction. This suggests that the alkali-soluble beta-glucan was converted to an alkali-insoluble product and possibly may be an intermediate stage in cellulose synthesis.
D000656:Amoeba / Q000201:enzymology / Q000378:metabolism*; D002250:Carbon Radioisotopes; D002482:Cellulose / Q000032:analysis / Q000096:biosynthesis*; D005947:Glucose / Q000378:metabolism; D005958:Glucosephosphates / Q000378:metabolism / Q000494:pharmacology*; D007700:Kinetics; D013997:Time Factors; D014532:Uridine Diphosphate Glucose / Q000378:metabolism*; D014539:Uridine Diphosphate Sugars / Q000378:metabolism*
D002250:Carbon Radioisotopes; D005958:Glucosephosphates; D014539:Uridine Diphosphate Sugars; D002482:Cellulose; D005947:Glucose; D014532:Uridine Diphosphate Glucose