Chemoenzymatic synthesis of glycoproteins.

The majority of the world's best-selling biotherapeutics are glycoproteins. However their production using cellular expression systems invariably produces inseparable mixtures of materials which differ in their attached carbohydrates. As in many cases correct carbohydrate structure is vital for in vivo efficacy, the development of methods for the production of glycoproteins in homogeneous form has become a significant scientific objective. Here a brief overview of recent progress in the production of homogeneous glycoproteins, including monoclonal antibodies, will be discussed, centring on the use of endo-β-N-acetylglucosaminidase (ENGase) enzymes for protein glycoengineering.