Flavin changes accompanying adaptation of Zymobacterium oroticum to orotate.

The preceding paper describes the purification of the enzyme dihydroorotic dehydrogenase from the obligate anaerobe, Zgmobacterium oroticum (1) The enzyme is formed adaptively when the bacteria are grown on a complex medium containing orotate as a major energy source. Purification of dihydroorotic dehydrogenase led to the demonstration that the enzyme is a flavoprotein (1, 2). It therefore seemed possible that the adaptation to orotate might be accompanied by a change in the flavin content of the bacterial cells. The present paper describes measurements of the flavin content of dihydroorotic dehydrogenase, and of cells grown with either glucose or orotate as the energy source. Data will be presented to confirm the conclusion that the enzyme contains flavin mononucleotide and flavin adenine dinucleotide in approximately equal amounts, and to show that the bacteria grown on orotate contain considerably more F,MNr and F,4D than bacteria grown on glucose.