The specific activities of two molybdenum hydroxylases; aldehyde oxidase and
xanthine oxidase from six tissues; (heart, jejunum, kidney, liver, lung and spleen), of
the Arabian one–humped camel, (Camelus dromedarius) were measured. Three
different substrates: 3-methylisoquinoline, phthalazine and phenanthridine were used
for aldehyde oxidase activity. Only liver had aldehyde oxidase activity with
phenanthridine as a substrate. Xanthine oxidase showed no activity in all the studied
tissues, with xanthine as a substrate. The values of both Vmax and Km were determined,
for hepatic aldehyde oxidase. The activity of aldehyde oxidase was completely
inhibited using menadione and hydralazine.