Abstract
Conditions for obtaining stable protoplasts from Sclerotium glucanicum and their reversion to hyphal growth were determined. 1,3-.beta.-Glucan synthase activity was detected in particulate enzyme fractions from mycelium and protoplasts of Scl. glucanicum. UDP-[U-14C]glucose was linearly incorporated into a .beta.-glucan for about 20 min at 25 .degree.C. Optimum pH and temperature values, as well as thermal stabilities of the 1,3-.beta.-glucan synthase activity, were determined. High concentrations of EDTA were inhibitory. Enzyme activity was stimulated by ATP and GTP. The apparent Km value for UDP-glucose was 0.54 mM. The reaction product was characterized as 1,3-.beta.-glucan by 13C NMR spectroscopy and hydrolysis products of an exo-1,3-.beta.-glucanase.