Polygenic control of aldehyde oxidase in Drosophila.

HEN extracts of wild-type Drosophila are electrophoresed on agar gels and the gels stained with a tetrazolium solution containing benzaldehyde, a formazan band is formed at a location not identical to the xanthine dehydrogenase (XDH) band ( COURTRIGHT 1966a). This was a surprising observation since benzaldehyde has been reported to serve as a substrate for XDH (GLASSMAN and MITCHELL 1959a). Since our new band is detected in extracts of ry flies, but not ma-1 flies, the evidence suggested that benzaldehyde was serving as a substrate for pyridoxal oxidase, a possibly related enzyme which also is present in ry and absent in ma-2 flies (FORREST, HANLY and LAGOWSKI 1961). The present paper presents genetic and biochemical evidence that the enzyme in question is neither pyridoxal oxidase nor XDH, but an aldehyde oxidase under similar genetic control. The enzyme also has some properties in common with the so-called ma-lf factor (GLASSMAN 1965, 1966), although its identity to the ma-l+ complementing factor is questionable.