Proteins and peptides are naturally occurring macromolecules responsible for the proper functioning of the body. Both consist of strings of the same essential building blocks, i.e., amino acids joined by peptide bonds.
But if they both are made up of the same things, what is the difference between them?
The most glaring distinction between proteins and peptides is their size or the number of amino acids they contain.
Peptides and proteins both have great potential as therapeutics. However, understanding their differences will allow you to reap the benefits of their health applications. However, before we jump to their differences, it’s crucial to understand what peptides and proteins are?
What are Peptides?
Peptides are small molecules made up of short chains of amino acids. They exist naturally in the human body, but you can also find them in plant and animal protein sources.
In peptides, each amino acid is attached to the chain through a peptide bond.
- Oligopeptides are peptides containing 2-10 amino acids. They include dipeptides, tripeptides, and tetrapeptides.
- Polypeptides are peptides containing more than 10 and up to 50 amino acids.
Since peptides have a lesser number of amino acids, they are primarily linear molecules. However, there are exceptions known as cyclotides, i.e., chains of amino acids joined to form a circle.
Structurally, peptides are similar to certain hormones because they can penetrate tissues and send information. Researchers isolate these peptides or make them by combining individual amino acids.
Nowadays, the synthesis of peptides and their applications are gaining popularity. As a result, various expert laboratories offer peptide synthesis services for clinical, analytical, and non-clinical purposes.
What are Proteins?
Proteins are made up of one or more polypeptides determined by the information encoded in the corresponding codon. These macromolecules are responsible for various functions in the body. Some of them are listed below.
- They are responsible for forming cellular structure – gives cells their shape and provides overall support for the body.
- They form antibodies by binding with foreign invaders like viruses to protect the body.
- They are responsible for the signal transduction process and sending messages between cells, tissues, and organs.
- They facilitate the transportation of molecules and atoms by binding and carrying them throughout the body.
Peptide Vs. Protein – How do they differ?
By definition, a peptide refers to a short chain of two or more amino acids connected in a sequence by a peptide bond. In contrast, a protein is a large polymer of fifty or more amino acids.
The sequence, shape, and composition of amino acids decide the core functionality of a protein or peptide. The key differentiators between both the biological molecules are as follows.
- Difference Based On The Number Of Amino Acids
- A peptide is a short chain of approximately 2-50 amino acids, for example, Neurokinin A – a neurotransmitter. It is a member of the Tachykinin neuropeptide family, sharing the C-terminal sequence Phe-X-Gly-Leu-Met-NH2.
- Proteins are polypeptides containing more than 50 amino acids., for example, Insulin – a hormone. It comprises two polypeptide chains – chain A and chain B of 51 amino acids in length.
- Difference Based On Structural Organization
Peptides usually have a primary structure, i.e., a straight chain of amino acids. In contrast, proteins have either secondary, tertiary, or quaternary structures.
- Difference Based On The Types Of Amino Acids
Proteins are only made up of 20 essential amino acids. In contrast, peptides are made up of both essential and other naturally occurring amino acids.
- Difference Based On Bonds
In peptides, the bonds joining amino acids are peptide bonds. In proteins, peptide bonds join amino acids to make polypeptide chains. In addition, other bonds like hydrogen bonds, hydrophobic and hydrophilic interactions, disulfide bonds, etc., occur between polypeptide chains of amino acids.
- Difference Based on Functionality
Proteins perform and regulate essential functions throughout the systems of the human body. In comparison, peptides play a crucial role in regulating other molecules’ activities, especially proteins.
Why Are Medical Researchers Excited About Peptides and Proteins?
When interacting with enzymes, proteins and peptides cause specific chemical reactions, leading to biological processes like cellular repair. And because of this trait, both of the molecules have high pharmaceutical potential.
Reports suggest that the market for protein and peptide drugs is more than 10% of the total pharma market. Furthermore, this market is exponentially growing in comparison to that of small molecules.
Synthetic peptides and recombinant proteins can imitate natural components in the body and make up for damaged/missing cellular constituents. Moreover, researchers believe that custom peptides can target a broad range of molecules, giving them endless possibilities in immunology, oncology, infectious disease, and more.
Currently, there are many approved peptide-based therapeutics in the market, with the majority being smaller than 20 amino acids. However, some peptide and protein-based medications for specific diseases are still in the pre-clinical and clinical trial phases.
Future Perspective
Peptides and protein therapeutics are revolutionizing medical therapy because of their broad applications and high target specificity.
Indeed, there are still issues and challenges to solve. Still, efforts are underway to improve the stability and oral availability of peptide therapeutics.
Discover more from Today Headline
Subscribe to get the latest posts to your email.