A bioinformatical approach suggests the function of the autoimmune hepatitis target antigen soluble liver antigen/liver pancreas

Antibodies to a soluble liver antigen/liver pancreas (SLA/ LP) appear to be highly specific for the diagnosis of autoimmune hepatitis. The SLA/LP targ et antigen was recently identified as a hitherto unknown gene encoding 474 amino acid residues. The function of this antigen remains unclear, because it does not share sequence homology with proteins of known function stored in any of the publicly accessible databases. Therefore we used a new theore tical method called fold recognition and could show that the SLA/LP sequenc e is compatible with the architecture of the superfamily of pyridoxal phosp hate (PLP; vitamin B6)-dependent transferases. Its function is likely to be that of a serine hydroxymethyltransferase and may be an important enzyme i n the thus far poorly understood selenocysteine pathway.