What Are Peptides?
Peptides and proteins are both made up of amino acids that are linked together (by peptide bonds, hence the name) in long chains called polymers. The only thing that separates peptides from proteins is how big they are. While there is no absolute cutoff, peptides are made up of fewer amino acids than proteins and hence are much smaller. In general, any amino acid chain that is longer than fifty residues in length is referred to as a protein. This is because after growing beyond 50 amino acids, peptides start to fold back on themselves creating shapes and bonds that are referred to as secondary structure. Peptides are almost always linear, with minimal secondary structure (lariat loops are sometimes observed), hence the size cut off.So, peptides are smaller, simpler versions of proteins. But saying that does not do justice to the role these biochemicals play in everyday life. Research shows that peptides are primarily signaling molecules used to alter the ebb and flow of major biological systems. Peptides influence things like immune regulation, growth hormone release, extracellular matrix production, nerve cell growth and migration, and much more. Peptides are the keys to starting and stopping major biochemical cascades and, as such, are of the utmost importance to proper biological function.It’s important to remember that we consume peptides on a daily basis. Eggs, milk, beans, meat, oats, and wheat all contain peptides, proteins, and various other biologically active molecules. In addition, many popular supplements, energy drinks, and health foods are enriched with peptides that help to improve body composition, boost energy, and aid digestion. Examples of common peptides found in everyday products include collagen and creatine.
Peptide Classes
Peptides are generally divided into groupings based on their function. For instance, there are antibacterial peptides, vaccine peptides, and anticancer peptides. Unfortunately, these peptide categories often overlap, which makes strict categorization difficult and confusing. For instance, brain peptides and immune peptides often overlap. The same is true of skin peptides and immune peptides as well as skin peptides and tendon peptides. Categorizing peptides by where they are located is an untenable approach because they are often found in various tissues.
