Importance & Structure
Proteins and peptides are omnipresent through all living organisms and therefore represent a central study focus in disease prevention and treatment research.
Proteins consist of more than one polypeptide: a single linear polymer chain of amino acids bound by peptide bonds between carboxyl and amino groups.
Peptides, in comparison to proteins, are short polypeptides, with less than 50 monomers and have a lower molecular weight, <10,000 g/mol.
Peptides consist of amino acid monomers, where each monomer binds to the next via a peptide bond (also known as an amide bond). Peptide bonds form by condensation; i.e. the loss of a hydrogen and oxygen from one amino acid’s carboxyl group (-COOH) as well as the removal of a hydrogen from the amino group (-NH2) of the other amino acid monomer. The condensation reaction leads to the formation of a water molecule and a peptide bond between the two amino acid monomers. Peptides can exist as either an oligomer or polymer, depending on the number of amino acid monomers within the peptide chain.
Protein Categories & Applications
Recombinant proteins are produced in the lab and purified to a high level. They originate from mammalian or human DNA cloned into bacteria, which then amplifies the desired protein to the required level. Recombinant proteins are applied in studies around cell growth, differentiation, and signaling, as well as disease onset and progression.
Collagen makes up the majority of the extracellular matrix; its fibrous structure is perfect for providing support most cells and tissues. It is helpful in studies involving cellular interactions and intracellular structure.
Cytokines, including chemokines, are small cell-signaling proteins which play a crucial role in immunomodulatory processes, inflammation, and cancer progression. They are regularly applied in ELISA, stem cell differentiation, and cell culture.
Extracellular matrix (ECM) proteins regulate cell adhesion, proliferation, differentiation, migration, survival, and invasion. These abilities are applied in vitro to ensure cells are anchored to plasticware and can grow efficiently, using minimal serum and growth factors.
Peptide Categories & Applications
Ribosomal peptides are synthesized by ribosomal translation of messenger RNA (mRNA). After mRNA translation, the amino acid sequence of the peptide is restricted and can no longer be changed. Usually, post-translational modification will occur after the ribosomal peptide is synthesized. Post-translational modification is essential for maturation of the synthesized polypeptide; this extends the biochemical properties of final proteins. Common mechanisms of post-translational modification include glycosylation, phosphorylation, hydroxylation, and sulfonation.
Non-ribosomal peptides are mainly synthesized by microorganisms like bacteria and fungi. Instead of ribosomes, non-ribosomal peptides are synthesized by an enzyme called non-ribosomal peptide synthase, in a process that is independent of mRNA. It is important to know that one type of non-ribosomal peptide synthase can only synthesize one type of peptide. Some examples of non-ribosomal peptides include antibiotics, pigments, and toxins.
Epigenetic peptides are useful for studying the regulation of gene expression, transcription and protein-protein interactions. They often consist of a histone peptide bound to biotin.
Beta Amyloid peptides aid in Alzheimer’s Research and Amyloid Beta degradation.
Peptides are useful in antibody production because the native protein is not always able to trigger an immune response in the organism. Therefore, synthetic peptides derived from native proteins are essential for an alternative method of antibody production. The most common method to induce an immune reaction in the animal is to couple the synthetic peptide with a carrier protein to enhance the efficiency. Antimicrobial and Anticancer peptides have also been shown to have significant potential for medical application.
Peptides are also regularly used in mass spectrometry, while synthetic variants are used to investigate protein-peptide interactions.