Posttranslational Modifications to Improve Biopharmaceuticals

Protein posttranslational modification (PTM) is a widespread phenomenon and such modifications can profoundly effect protein properties relevant to their therapeutic application. The majority of protein-based biopharmaceuticals approved or in clinical trials bear some form of PTM. While glycosylation represents the most common modification, additional PTMs including carboxylation, hydroxylation, sulfation, and amidation are characteristic of some products. The relationship between structure and function is understood for many PTMs but remains incomplete for others, particularly in the case of complex PTMs such as glycosylation. A better understanding of such structure-functional relationships will facilitate the development of second-generation products displaying a PTM profile engineered in order to optimize their therapeutic usefulness. This approach is exemplified by the recent development of glycoengineered antibodies displaying improved therapeutic characteristics.