Identification of alpha 1-acid glycoprotein (orosomucoid) in human synovial fluid by capillary electrophoresis.

Capillary electrophoresis of human synovial fluid in a phosphate borate run buffer containing sodium dodecyl sulphate separates a hydrophilic glycoprotein, hyaluronan and a number of low-molecular-mass components. The hydrophilic glycoprotein is identified as alpha 1-acid glycoprotein (AGP), orosomucoid, by co-injection methods with human AGP and by reaction with neuraminidase which released N-acetylneuraminic acid. Finally, a sample of the glycoprotein was isolated by micropreparative capillary electrophoresis, examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis methods and shown to give a positive reaction with AGP antibodies. The peak due to AGP in the capillary electrophoresis is broad and gives evidence for the presence of glycoforms.