Class-II dihydroorotate dehydrogenases from three phylogenetically distant fungi support anaerobic pyrimidine biosynthesis

Table 3 Dihydroorotate-dehydrogenase activities in cell extracts of S. cerevisiae strains expressing different DHODs, measured with different electron acceptors

Electron acceptor	DHOD activity (μmol·mg protein⁻¹·min⁻¹)
	S. cerevisiae IMK824 ura1Δ	S. cerevisiae IME603 mcScURA1	S. cerevisiae IME569 ura1Δ mcArura9
–	< 0.005	0.010 ± 0.001	0.008 ± 0.001
PMS	< 0.005	0.111 ± 0.007	0.132 ± 0.029
Fumarate	< 0.005	0.110 ± 0.020	0.006 ± 0.000
NAD⁺	< 0.005	< 0.005	< 0.005
NADP⁺	< 0.005	< 0.005	< 0.005
Q_D	< 0.005	0.033 ± 0.022	0.009 ± 0.003
FMN	< 0.005	0.037 ± 0.002	0.126 ± 0.012
FAD	< 0.005	0.011 ± 0.002	0.148 ± 0.032

Activities were measured in S. cerevisiae strains IMK824 (ura1Δ), IME603 (expressing ScURA1 from a multicopy plasmid) and in the strain IME569 (expressing Arura9 from a multicopy plasmid). Activities were measured without addition of electron acceptor (-), 0.1 mM phenazine methosulfate (PMS), 1 mM fumarate, 1 mM nicotinamine adenine dinucleotide (NAD⁺), 1 mM nicotinamide adenine dinucleotide phosphate (NADP⁺), 0.1 mM decylubiquinone (Q_D), 20 μM flavin mononucleotide (FMN) or 20 μM flavin adenine dinucleotide (FAD). Activities are represented as the average ± mean deviation of activities measured with two independently prepared cell extracts

ISSN: 2054-3085