If you ask anyone, “What is a peptide?”, you will probably get a stock answer involving a chain of 2 or more amino acids which link together via a “peptide” linkage (-C(O)-NH). You might learn there are 20 natural amino acids, and they are all in the same L- stereo configuration. You might also learn that they are great at getting the body to do stuff, but they don’t make great drugs because they have short half-lives. So, we need to modify natural peptides so that they behave more like drugs – we’ll find ways to make them more stable – but still have them doing all the nice things we like about them. We’ll cyclise them, stick fat on them, PEGylate them, conjugate them to make them better.
This article looks at some of the ways peptides are modified, but also recognizes that unmodified peptides still have a role to play.
