Deglycosylation of Antibodies

Antibodies, the protein substances that the body produces to fight pathogens or disease-causing organisms, often have protective sugars called glycans attached to them. "Deglycosylation of antibodies" means removing these glycans. Deglycosylation occurs both in nature and in the laboratory.

Deglycosylation in Nature

• Deglycosylation can occur without human intervention. For example, immunoglobulin A1, an antibody that fights periodontal disease, has a protective nine-carbon glycan called sialic acid attached to it. But various pathogens can remove sialic acid from the antibody, thereby rendering it vulnerable to further degradation, according to Acta Pathologica, Microbiologica et Immunologica.

Reasons for Deglycosylation

• In the laboratory, scientists may remove a glycan from its antibody for several reasons. The attached sugar hinders such operations as polyacrylamide gel electrophoresis, a process for segregating antibodies and other proteins by weight. In addition, scientists may want to study the protein alone, using mass spectrometry. Or they may want to study the glycan.

Methods

• Scientists remove glycans by an enzyme plus applying heat, provided that the glycan is attached to a nitrogen atom of a protein component called asparagine. Using a microwave instead of ordinary heat will greatly accelerate the deglycosylation process so that it takes a few minutes instead of hours. It is harder to remove a glycan attached to the oxygen atom of such protein components as threonine. Several steps are required.