Regional assignment of the human gene coding for a multifunctional polypeptide (P4HB) acting as the beta-subunit of prolyl 4-hydroxylase and the enzyme protein disulfide isomerase to 17q25.

Prolyl 4-hydroxylase, an alpha 2 beta 2 tetramer, catalyzes the formation of 4-hydroxyproline in collagens and related proteins by hydroxylating proline residues in peptide linkages. The beta-subunit of prolyl 4-hydroxylase (P4HB) is a highly unusual multifunctional polypeptide that is identical to the enzyme protein disulfide isomerase and a major cellular thyroid hormone-binding protein and is highly similar to a glycosylation site-binding polypeptide of oligosaccharyl transferase. We report here the regional assignment of the gene for this multifunctional polypeptide. In situ hybridization mapped the gene to 17q25. Southern blot analyses of restricted DNA from a chromosome-mediated gene transfer transfectant panel suggested that the P4HB gene is located distal to the gene for thymidine kinase, either between the genes for thymidine kinase and galactokinase or on the telomeric side of both these genes.