InterPro: IPR006231 Malate:quinone-oxidoreductase

The membrane-associated enzyme, malate:quinone-oxidoreductase, is an alternative to the better-known NAD-dependent malate dehydrogenase as part of the TCA cycle. The reduction of a quinone rather than NAD+ makes the reaction essentially irreversible in the direction of malate oxidation to oxaloacetate. Both forms of malate dehydrogenase are active in Escherichia coli; disruption of this form causes less phenotypic change. In some bacteria, this form is the only or the more important malate dehydrogenase [1].