Peptides: What Are They?
Peptides are biological materials that are made from building blocks called amino acids. Animals get most of their amino acids from the foods they eat. Different cells then assemble these amino acids into long chains called peptides or proteins. As the chains grow in length, they are able to fold back on themselves. Certain amino acids can interact with one another when peptide chains fold, resulting in the folds being locked into place under normal physiologic conditions. This gives the peptide chain a three-dimensional structure. The length and order of the amino acids in the peptide determine its folding and ultimate three-dimensional structure.
Receptors and Protein Interactions
Receptors are special biological machines to which proteins can bind. They only accept proteins that have the right order of amino acids and the right three-dimensional shape. By varying these properties, it is possible to create proteins with specific and diverse functions. Research studies have shown that peptides binding to receptors in one part of the body may not interact with receptors in other parts. This specificity allows for the transmission of specific signals and coordinated actions, such as immune function and carbohydrate metabolism.
There is no formal definition for what makes a peptide “small,” but they often lack extensive three-dimensional structure. They may have a fold or two, but not much beyond that. Small peptides rely more on their amino acid sequence than their three-dimensional structure for signaling. Even a small change in the order or number of amino acids can significantly impact the receptors they can bind to. Sometimes, a single amino acid change is enough to completely alter the function of a small peptide.
The Future of Small Peptides
In the past, the focus of research was primarily on larger peptides and massive proteins, assuming that biologically active proteins were large. It was thought that mimicking existing proteins exactly was the best approach to develop therapeutics. However, new research indicates that small peptides are not only easier to make but also have a wide range of biological activity. Mimicking naturally occurring proteins is no longer considered the best strategy for therapeutic development. Small peptides have shown applications in antibiotics, heart medications, disease prevention (e.g., diabetes), and even anti-aging effects in animal models.
The future of medicine will see an increasing use of small peptides. While they won’t be the sole therapeutics available, they will comprise a significant portion of substances used to promote health. Small peptides can be custom-made to combat diseases and preserve health. They are less complex to synthesize and produce, and insights gained from early research trials will shape future advancements. It’s expected that within the next couple of decades, small peptides will be as commonplace in the medical field as antibiotics and vaccines are today.