Peptides

Peptides are short chains of amino acids linked by peptide (amide) bonds. The defining feature that distinguishes peptides from proteins is size. A rule of thumb often used is that peptides are typically made up of 50 or fewer amino acids, while proteins consist of more than 50 amino acids^[1]. However, this cutoff isn't always strictly applied, and you may find some variance in the literature.

Amino acids are the building blocks of peptides and proteins. Humans utilize 20 standard amino acids, each with a unique side chain or "R group" that determines its properties. Amino acids are connected to one another in a specific sequence by peptide bonds, which are formed through a dehydration synthesis reaction, where a molecule of water is released.

The sequence of amino acids in a peptide or protein is determined by the sequence of a gene, which is translated into a protein by the machinery in a cell. The specific sequence of amino acids in a peptide or protein ultimately determines its 3D structure and its function in the body.

Peptides can have a wide variety of functions in the body. Some act as neurotransmitters, others as hormones. Some regulate physiological functions or serve structural roles.

Peptide synthesis, the process of peptide production, can occur naturally within the body or artificially in the lab. Artificial peptide synthesis is a key technique in biochemistry and molecular biology, facilitating the study of peptide structure and function, as well as the development of new therapeutic agents.

Many pharmaceutical drugs are based on natural peptide structures or are synthetic peptides^[3].