A STUDY OF VIABILITY AND TREHALOSE METABOLISM IN SACCHAROMYCES-CEREVISIAE VACUOLAR DEFICIENT MUTANT SKD2

The vacuolar deficient mutant SKD2 and a closely related vacuole compl ete strain SKDl rho(-) were studied to identify the cause of low treha lose accumulation in SKD2. The present work indicates that low intrace llular trehalose levels in SKD2 result from reduced activity of enzyme s of the trehalose-6-phosphate synthase/phosphatase complex rather tha n higher activity of trehalase in the cytosol caused by supposed ineff ective compartmentalisation of vacuolar acid trehalase. in vitro studi es using crude enzyme extracts from SKDZ and SKD1 rho(-) also suggeste d that loss of viability of SKDZ might result from a fall in free phos phate levels as sugar phosphates accumulated.