Purification of aldehyde oxidase from bovine ciliary body

Ocular aldehyde oxidase was purified for the first time from bovine ciliary body cytosol by ammonium sulfate fractionation and successive HPLC using DEAE anion-exchange and hydroxyapatite columns. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be about 150,000 by electrophoresis and to be about 300,000 by gel filtration HPLC on a TSK gel G3000SWXL column, indicating that the enzyme consists of two subunits with the same molecular weight. On the other hand, nicotinamide N-oxide reductase activity was associated with aldehyde oxidase activity throughout the purification steps of the latter enzyme. This fact indicated that nicotinamide N-oxide reductase activity of the ciliary body cytosol is due to aldehyde oxidase present in the tissue preparation.