“…It thus appears that the succinate dehydrogenase complex (SDHC), a tetramer of Sdh1, Sdh2, Sdh3 and Sdh4 (Lombardo et al, 1990;Chapman et al, 1992;Bullis and Lemire, 1994;Daignan-Fornier et al, 1994), is the only TCA cycle-specific enzyme required for acetate utilization on YNBA. Our results also show that the enzymes involved in the glyoxylate cycle operation, such as ACO (Aco1) (Gangloff et al, 1990), malate synthase (Mls1) (Hartig et al, 1992;Kunze et al, 2002), isocitrate lyase (Icl1) (Fernandez et al, 1992;Taylor et al, 1996) and Mdh2 (Minard and McAlister-Henn, 1991), are indispensable for the growth of yeast cells with acetate on YNBA, regardless of their involvement in the TCA cycle. Considering that both the cytoplasmic and mitochondrial isoforms of fumarase (FUM) are encoded by a single gene, FUM1 (Wu and Tzagoloff, 1987), and that operation of the TCA cycle is dispensable on YNBA, as shown above, it is suggested that conversion of fumarate to malate Figure 6.…”