Glycogen synthase of Schistosoma mansoni: a preliminary report
Rotmans, J.P.
Acta Leidensia 48: 29-36
1980
ISSN/ISBN: 0065-1362 PMID: 6789597 Document Number: 165003
Glycogen synthase activity was not detectable in crude homogenates of Schistosoma mansoni, but was detectable in a 200 000 g pellet of worm homogenate. Further purification was obtained by gel filtration of the enzyme-glycogen complex. Specific activity of the preparation varied between 10 and 30 mU/mg protein. Further purification met with serious difficulties as removal of glycogen increased greatly the instability of the enzyme. In the presence of 5 mM glucose-6-phosphate the reaction obeyed Michaelis-Menten kinetics with respect to UDP-glucose as substrate, and the Km for UDP-glucose was 2.4 mM. No inhibition of the enzyme activity was observed at high concentrations of UDP-glucose. A Km for glycogen could not be determined, since the high amount of glycogen already present saturated the enzyme. A 2-fold increase in enzyme activity was obtained at a glucose-6-phosphate concentration of 12 mM. The ratio of active and inactive glycogen synthase did not change when the enzyme preparation was obtained from worms from hamsters which had been fasted for 2 days.