Comparative biochemical and genetic studies of the GOX-1 (HAO-1) and the XDH-1 polymorphism in the rat (Rattus norvegicus).

Biochemical and genetic studies have been carried out to test whether the GOX-1 (HAO-1) and the XDH-1 polymorphism in the rat are determined by one locus or by two different closely linked loci. Besides similar migration behaviour upon electrophoresis the phenotypes of both polymorphisms share major biochemical properties such as responses to heat inactivation at 50 and 70 degrees C and isoelectric points. This suggests that they represent only one enzyme. The one-enzyme hypothesis is supported by linkage analyses performed in 50 offspring of a backcross population [(SPRD-Cu3 x BN)F1 x SPRD Cu3] and 14 LXB recombinant inbred strains (progenitor strains LEW and BN) in which not a single recombinational event can be observed. The latter finding agrees well with the GOX-1/XDH-1 distribution pattern investigated in 93 inbred strains and substrains (BENDER et al. 1984). Because of these results and due to a preferential reactivity with glycolic acid we propose to designate this polymorphism only as glycolate oxidase (GOX-1).