1.3.98.1 S175A - 390913 1.3.98.1 R265A 2fold increase in KM-value of CoQD, 15% increase in KM-value of L-dihydroorotate 656285 1.3.98.1 H185A 4fold increase in KM-value of CoQD, 50% increase in KM-value of L-dihydroorotate 656285 1.3.98.1 L71F/C130S/V133T addition of the two residues comprising the conserved proton-transfer network of Class 2 dihydroorotate dehydrogenase from Escherichia coli to the C130S Class 1A enzyme of Lactococcus lacits. Mutation does not did not restore the function of the active site base or rapid flavin reduction. Kd for dihydroorotate is about three times tighter than the wild-type 724305 1.3.98.1 E206/K296E conversion of intermolecular salt bridge, mutant is fully active in concentrated solutions and dissociates into monomers upon dilution like wild-type enzyme 657291 1.3.98.1 K213E decrease in activity against dichlorophenolindophenol 656148 1.3.98.1 P131A decrease in activtiy against fumarate 656148 1.3.98.1 S129A decrease in activtiy against fumarate 656148 1.3.98.1 additional information deletions of N-terminal residues from 2 down to 40 result in generally unstable proteins with apo protein quickly precipitating and FMN remaining in solution. A truncated protein lacking residues 2 to 30 is sufficiently stable, has near to wild-type activity using molecular oxygen and 20fold lower activity using 2,6-dichlorophenolindophenol as electron acceptor 657355 1.3.98.1 additional information DHOD-knockout Trypanosoma cruzi do not express the enzyme protein and can not survive even in the presence of pyrimidine nucleosides, suggesting a vital role of fumarate reductase activity in the regulation of cellular redox balance 675478