Immunological heterogeneity of hepatic alanine:glyoxylate aminotransferase in primary hyperoxaluria type 1.

Immunoblotting of human liver sonicates, after SDS-polyacrylamide gel electrophoresis, demonstrated the presence of a 40 kDa protein, corresponding to the subunit of alanine:glyoxylate aminotransferase, in six controls and three patients with primary hyperoxaluria type 1 (peroxisomal alanine:glyoxylate aminotransferase deficiency). This immunoreactive 40 kDa protein was absent in a further nine patients. Subcellular fractionation of patients' livers showed that the 40 kDa protein, when present, was located mainly in the peroxisomes. In a heterozygote liver, the 40 kDa protein was also mainly peroxisomal and paralleled the distribution of alanine:glyoxylate aminotransferase activity.