Peptides are increasingly being identified as a key component of drug discovery, drug design, and pharmaceutical research. Through the use of peptides, researchers can identify the specific functions of potential drug leads, resulting in faster, more efficient, and more targeted drug research.
But where do peptides come from? How is it that they’re so powerful and versatile? Peptides are useful because they are, in essence, purified biological information and activity.
Peptide Origins
To understand where peptides come from, one must first understand a bit about proteins. Proteins are the true origin of natural peptides and are essentially large biological molecules that provide most of the activity and interaction within a cell.
Proteins serve a wide variety of functions within nutrition, metabolism, and the catalyzation of chemical reactions within the human body: proteins can make energy available during digestion by providing essential amino acids, but conversely proteins can be agents of allergic reactions.
The biological actions performed by proteins are dictated by peptides, which are themselves chains of amino acids within a larger protein framework. Peptides, then, are most useful because they contain within their structures specific coded instructions as to the function carried out by a protein.
As peptides are isolated from proteins, the amino acid chains being tested are smaller. Smaller amino acid chains mean that the range of possible activities performed by that test material is smaller still. The goal of drug discovery is to target specific information within a molecule that performs a specific action, and so peptide testing is ideal for that research targeting.
How Are Natural Peptides Produced?
Proteins provide an abundance of information and possible activities within a biological system. Removing peptides from proteins reduces the potential activities being provided, and so reduces the possible sources of information to be used in drug research.
At a basic level, peptides are produced naturally within any biological system that produces proteins. These peptides work within proteins to perform specific functions and can be broken, reformed, or take different peptide forms, depending on their functional activity.
For natural peptides, testing occurs to identify the activity of certain peptides within an organism that exhibits a desirable trait. Once researchers have determined activity of interest within a peptide, then the peptide can be isolated from its protein.
Naturally occurring peptides are designed and evolved through organic biological systems and are purified through a series of techniques that remove them from their protein superstructure. These techniques break the peptide bonds within a protein and then utilize centrifuges to remove peptides from unwanted material.
How Are Synthetic Peptides Produced?
Natural biological peptides, being designed through organic systems, can have undesirable, inefficient, or even harmful traits that decrease their usefulness in drug research. It is because of this natural disadvantage that researchers have turned to peptide mimetics to imitate the activity of certain peptides in a synthetic system.
Peptide mimetics mimics natural peptides through targeting multiple small molecules at the same activity performed by the natural peptide, but now with fewer impurities or distracting traits. Synthesis of these peptides occurs by disassembling the original, natural peptide, then reconstructing a new molecule made up of only the essential, desired features on a mimetic scaffold.
This synthetic peptide synthesis process can be laborious, as researchers can require many assays to achieve the desired result. Several rounds of peptide design can result from this reconstruction process; in each round, the test synthetic peptide is analyzed for structure-activity relationships that demonstrate the required activity. After each round, the proposed structure of the synthetic peptide is altered to reflect the new understanding of its activity.
Synthetic peptides, when successfully designed, are designed to be far more efficacious than their natural counterparts. Whatever their origin, both naturally derived and synthetically produced peptides originally come from nature and its organic biological processes.
