Orosomucoid (alpha-1 acid glycoprotein) phenotyping by use of immobilized pH gradients with 8M urea and immunoblotting

Summary Orosomucoid (ORM) phenotyping has been performed on 329 unrelated Swiss subjects, using immobilized pH gradients with 8M urea and 2% v/v 2-mercaptoethanol followed by immunoblotting. After desialylation the band patterns of ORM confirmed that the polymorphism of the structural locus ORM1 is controlled by three codominant autosomal alleles (ORM1^*F1, ORM1^*S and ORM1^*F2). One rare and one new allele were detected. The rare variant, tentatively assigned to the second structural locus ORM2, is observed in a cathodal position and named ORM2 B1. The new variant, tentatively assigned to the first structural locus ORM1, is observed in a region located between ORM1 S and ORM1 F2, and named ORM1 F3. Moreover, the pI values of the ORM variants have been measured accurately with Immobiline Dry Plates (LKB): they were found to be within the pH range 4.93–5.14.