ABSTRACT
Peptides and proteins have been used for decades as pharmaceuticals to treat life-threatening diseases, and 95 years ago insulin was among the rst plasma-derived proteins used to effectively treat a fatal disease. In 1920, Frederick Banting and Charles Best isolated and puried insulin while working in the laboratory of Professor John Macleod at University of Toronto, and saved the life of 14-year-old Leonard Thomson, a type I diabetic, by injecting him with insulin. Other proteins like factor VIII (hemophilia) and XI, INF-β1 (multiple sclerosis), anti-TNFα (inammation), and
9.1 Introduction .......................................................................................................................... 137 9.1.1 A Historical Perspective ........................................................................................... 137 9.1.2 Aspects of Peptide and Protein Drug Design ........................................................... 138
9.2 Peptide and Protein Protraction ............................................................................................ 139 9.2.1 Polymer Extension .................................................................................................... 139
9.2.1.1 PEGylation ................................................................................................. 139 9.2.1.2 Polypeptide Modication ........................................................................... 141 9.2.1.3 Carbohydrate-Based Polymer Modication .............................................. 141
9.2.2 Albumin as Protractor .............................................................................................. 142 9.2.2.1 Reversible Binding by Fatty Acid Acylation.............................................. 143 9.2.2.2 Reversible Binding by Other Moieties ....................................................... 144 9.2.2.3 Fusion Proteins and Conjugates ................................................................. 145
9.2.3 Fc-Fusions and Conjugates ....................................................................................... 145 9.3 Peptide and Protein Engineering .......................................................................................... 146
9.3.1 Increasing the Enzymatic Stability ........................................................................... 146 9.3.1.1 Global Modications ................................................................................. 146 9.3.1.2 Peptide Bond Modication ........................................................................ 147
9.3.2 Methods for Structure-Activity Relationship........................................................... 148 9.3.2.1 Replacement and Analysis ......................................................................... 148 9.3.2.2 Multi-Parallel Synthesis and Peptide Arrays ............................................. 149
9.3.3 De Novo Design ........................................................................................................ 150 9.3.3.1 Biological Approaches ............................................................................... 150 9.3.3.2 Synthesis Approach ................................................................................... 150
9.3.4 Chemical and Biophysical Stability .......................................................................... 151 9.3.5 Immunogenicity ........................................................................................................ 152
9.3.5.1 Predicting Immunogenicity ....................................................................... 153 9.4 Concluding Remarks ............................................................................................................ 153 Further Reading .............................................................................................................................153
growth hormone have since demonstrated great therapeutic value. With the entrance of recombinant technology in the late 1970s it became possible to design analogs of natural proteins in expression systems like E. coli, yeast, or various mammalian cells. It was now possible to make mutations in a protein, or, native-like post-translational modications such as glycosylation, giving rise to protein analogs with altered and/or improved properties. Rapid acting insulin analogs like insulin aspart or insulin lispro were the rst protein analogs to enter the market. They were engineered so one or two mutations in the dimer interface destabilized the dimer formation leading to preferentially monomeric insulin which in turn led to a more rapid acting analog than native insulin.
