Attività UDPG pirofosfatasica in Cucurbita e suo possibile rapporto con l'utilizzazione del galattosio

Abstract

UDPG-PYROPHOSMIATASE ACTIVITY IN CUCURBITA AND ITS POSSIBLE ROLE IN GALACTOSE UTILIZATION. — Preparations obtained by ammonium sulfate precipitation from homogenates of Cucurbita maxima tissues catalyze the hydrolysis of UDPG to UMP and Gl-l-P. The same tissues contain all the enzymes implicated in galactose metabolism, with the exception of Gal-l-P-uridyltransferase. Therefore the possibility is suggested that the UDPG-pyrophosphatase found may play an important role in the conversion of galactose to the phosphate esters of glucose. This suggestion is also supported by the finding that the amount of activity found in homogenates could account for the respiratory activity of the tissues if glucose arising from galactose were the main respiratory substrate.