Isolation and Purification of the Down Syndrome Protein

Abstract

The presence of the Down syndrome (DS) protein in the sera of individuals is associated with a higher than average risk of parenting a child with Down syndrome. The protein has been determined to be a lipoprotein and is presumably a variant of β-lipoprotein.

Isolation of the DS protein is accomplished by means of hydroxylapatite chromatography. Elution of the protein is achieved in 7.5 hours via a 5 phosphate buffer scheme utilizing successively increasing phosphate concentrations while maintaining constant pH.

Immunoelectrophoretic and SDS-PAGE techniques have been used to assess the composition of the fraction resulting in the DS protein being obtained with a high degree of purity.

Key Words:

• Down syndrome protein
• hydroxylapatite chromatography
• crossed immunoelectrophoresis
• sodium dodecyl sulfate-polyacrylamide gel electrophoresis