| Aldehyde oxidase (AO) is a cytosolic molybdenum-containing hydroxylase. It is found in the highest concentrations in the liver and intestines of humans and other mammals but is also expressed in a variety of other organs, such as the kidney, lung and brain. The aim of this research was to investigate AO activity in bovine kidney and to determine if bovine kidney AO contributes to the metabolism of xenobiotics. Five known substrates for AO were evaluated to quantify AO activity in the kidney and these values were then compared to rabbit liver and bovine liver activities. Experiments with two known inhibitors of AO, menadione and methanol, were performed to help verify that the activity found in the partially purified enzyme preparations were catalyzed by AO. For all substrates evaluated, rabbit liver showed the highest activity followed by bovine liver and then bovine kidney. No measurable activity for the bovine kidney enzyme was observed with phenanthridine or methotrexate as substrates. However, bovine kidney AO catalyzed the oxidation of benzaldehyde, phenazine methosulfate and N1-methylnicotinamide. In conclusion, low levels of aldehyde oxidase activity were measured in the bovine kidney using xenobiotic substrates. |
