cDNA cloning, sequencing, and characterization of male and female rat liver aldehyde oxidase (rAOX1) - Differences in redox status may distinguish male and female forms of hepatic AOX

Molecular characterization of male and female rat liver aldehyde oxidase is reported. As described for the mouse liver, male and female rat liver expr essed kinetically distinct forms of aldehyde oxidase, Our data suggest that the two forms arise as a result of differences in redox state and are most simply explained by expression of a single gene encoding aldehyde oxidase in rats, In support of this argument we have sequenced cDNAs from male and female rat liver, We examined mRNA expression by Northern blot analysis wit h RNA from males and females, from several tissues, and following androgen induction. Purified rat liver enzyme from males or females revealed a singl e 150-kDa species consistent with cDNA sequence analysis. Both male and fem ale forms were reactive to the same carboxyl-terminal directed antisera. K- m(app) values obtained in crude extracts of male or female rat liver and po st-benzamidine-purified aldehyde oxidase differed substantially from each o ther but could be interconverted by chemical reduction with dithiothreitol or oxidation with 4,4'-dithiodipyridine, Our data indicate that a single ge ne is most likely expressed in male or female rat liver and that the kineti c differences between male and female rat liver aldehyde oxidases are sensi tive to redox manipulation.