THE PRESENCE OF AN ACTIVE S-ADENOSYLMETHIONINE DECARBOXYLASE GENE INCREASES THE GROWTH DEFECT OBSERVED IN SACCHAROMYCES-CEREVISIAE MUTANTS UNABLE TO SYNTHESIZE PUTRESCINE, SPERMIDINE, AND SPERMINE

Saccharomyces cerevisiae spe1 Delta SPE2 mutants (lacking ornithine de carboxylase) and spe1 Delta spe2 Delta mutants (lacking both ornithine decarboxylase and S-adenosylmethionine decarboxylase) are equally una ble to synthesize putrescine, spermidine, and spermine and require spe rmidine or spermine for growth in amine free media. The cessation of g rowth, however, occurs more rapidly in spe1 Delta SPE2 cells than in S PE1 spe2 Delta or spe1 Delta spe2 Delta, cells. Since spe1 Delta SPE2 cells can synthesize decarboxylated adenosylmethionine (dcAdoMet), the se data indicate that dcAdoMet may be toxic to amine-deficient cells.