The NADP-linked aldehyde reductase of Leishmania donovani

An enzyme that oxidizes ethanol to acetaldehyde in the presence of NADP (but not NAD) and reduces acetaldehyde to ethanol in the presence of NADPH (but not NADH) is present in Leishmania donovani promastigotes. The activity is present only in the supernatant fraction obtained from sonication of the cells and high speed centrifugation. The Km and Vm values were evaluated for propanol and propionaldehyde as well as for ethanol and acetaldehyde in cells obtained from late log and 3-day stationary phase cultures. There was no significant change in Km or Vm values for any of these four substrates with culture age. Since the Km values for ethanol and propanol are much higher than for the corresponding aldehydes and higher than any physiological range of alcohol concentration likely to be encountered, this enzyme is considered to function as an aldehyde reductase.