Metabolism of Trehalose in <i>Euglena gracilis</i>

Abstract

Phosphoglucomutase for β‐glucose 1‐phosphate, an enzyme present in cell‐free extracts of Euglena gracilis var. bacillaris , catalyzes the reversible conversion of β‐glucose 1‐phosphate to glucose 6‐phosphate. It was purified 460‐fold by treatment with protamine sulphate, gel filtration in Sephadex G‐100 and chromatography on a DEAE‐cellulose column. The optimum pH of the reaction was 7.0 and the equilibrium constant β‐glucose 1‐phosphate/glucose 6‐phosphate was 0.035. The enzyme has an absolute requirement for β‐glucose 1,6‐bisphosphate as well as a bivalent cation such as Mg 2+ , Co 2+ or Mn 2+ . Measurements in Sephadex G‐100 gave an apparent molecular weight of about 27000. This enzyme together with a trehalose phosphorylase found in the same Euglena extracts would constitute a new catabolic pathway for trehalose. The functions of α‐ and β‐glucose 1,6‐bisphosphate as regulation factors in the energy furnisher system in Euglena is discussed.