A Peptide Synthesis is a compound constituting amino acids linked together via peptide bonds to form an amino short, linear amino acid chain. Peptides occur naturally and serve multiple functions, including being protein building blocks. Proteins regulate fundamental cellular processes, including cell growth, structure, signaling, and transportation; peptides as protein building blocks influence these functions to some degree.
Peptides are essential compounds, and technological advances facilitate artificial peptide production for commercial use. However, is peptide synthesis a necessary function? What does it entail, and what are its applications? Keep reading to learn everything you need to know about peptide synthesis.
What Exactly Is Peptide Synthesis?
Peptide synthesis is the process utilized to form peptide or amide bonds between amino acids. An amide bond occurs after a condensation reaction entailing the removal of a water molecule, causing the carboxyl group (C-terminal) and the amine (nitrogen/N-terminal) group in amino acid monomers to link up, forming a polymer (chain). Peptide synthesis occurs in the C-terminal to N-terminal directionality, opposite to the condensation reaction utilized in protein synthesis.
The first historical account of in vitro peptide synthesis was in 1901. However, processes like solid-phase peptide synthesis have revolutionized peptide synthesis, facilitating custom peptide production.
Between 1901 and the 1960s, scientists used classic peptide production methods like liquid-solution phase peptide synthesis to generate popular peptides like insulin and growth hormones. However, the process was slow and labor-intensive because it entailed crystallizing and purifying the peptide precursor after each step.
However, solid-phase peptide synthesis (SPPS) replaced liquid/ solution phase peptide synthesis in the 1960s as a faster and more efficient in vitro peptide production method. SPPS entails the addition/linking of an amino acid’s functional carbon group (acylation) to an insoluble polymeric support, facilitating the high-speed generation of a linear, flexible peptide chain.
According to one study, SPPS has multiple advantages over classic synthetic peptide production methods, including rapid peptide production, the ease of building complex peptides, and fewer purification steps. Consequently, SPPS is the current industry standard for peptide synthesis.
However, liquid-phase peptide synthesis is not yet obsolete and can be preferable, depending on the peptide type. Moreover, one study shows that using solution-phase peptide synthesis alongside modifications like the Group-assisted Purification(GAP) Strategy helps improve the classical method’s efficiency.
Therefore, the ideal peptide synthesis method depends on the peptide type and intended use. Peptide production companies offer various services, including custom peptide synthesis to generate suitable peptides for the peptide applications explored below.
Peptide Synthesis Applications
Synthetic peptides produced via SPPS and LPPS have multiple industry applications across different fields. Below is an overview of the most popular artificial peptide applications.
Despite the numerous roles peptides play in human biological functions, researchers are yet to understand peptides fully and unlock their full potential. Therefore, peptide research must understand different peptides and utilize or improve their functionality.
Although the human body produces peptides, native peptides available in the body have multiple disadvantages that can hamper research. One literature review highlights physical and chemical instability and a short half-life as the primary intrinsic weaknesses of native peptides. However, synthetic peptides are more stable and mimic most native peptide functions; hence, they are better research alternatives.
Notable areas of peptide research include substrate interaction, epitope mapping, and clinical research. Substrate interaction explores the relationship between an enzyme and a substrate, or the substance on which it acts.
Besides enzyme concentration, enzyme binding sites influence the formation of the enzyme-substrate complex and the enzyme’s ability to trigger or impede specific biochemical processes. Therefore, enzyme-substrate interaction studies using peptides help enhance enzyme performance for a targeted effect.
On the other hand, epitope mapping is a research process that utilizes experiments to identify antibody binding sites on antigens or substances that trigger immune responses. It is the basis for immunotherapy research and development. Lastly, clinical research explores the clinical importance of peptides, including human clinical trials to establish the human response to different synthetic peptides.
Therapeutics and Drug Discovery
One breakthrough resulting from peptide research is the development of peptide therapeutics as a sub-field in drug discovery. Therapeutic peptides are pharmacological agents designed to harness peptides’ cellular functions for disease treatment and management. Such agents target and manipulate cells involved in pathogenic pathways, eliciting a response that helps cure or mitigate an illness’s effects.
An example of peptide use in therapeutics is the development of synthetic insulin to manage type 1 and 2 diabetes. Although insulin was the first peptide drug, it set a precedent for developing other peptide drugs. According to one report, 80 FDA-approved peptide drugs are available for administration to patients with various chronic health conditions, including HIV, osteoporosis, multiple sclerosis, and chronic pain.
However, the biggest win for peptide therapeutics is the development of cancer treatments via hormonal-based peptide therapies. Therefore peptide therapeutics are the future of drug discovery.
Vaccination or preventative therapy entails boosting the body’s capacity to fight diseases. Multiple vaccine types exist, including the classical live attenuated vaccines, with their administration entailing injecting a neutralized pathogen into the body. However, while helpful, such vaccines have multiple disadvantages, including safety issues arising from pathogen genetic variability and biological matter triggering unwanted reactions.
In contrast, peptide vaccines feature peptide fragments with an epitope from the pathogen to trigger an immune response rather than the entire organism. The synthetic nature of peptide vaccines means they pose no risk of non-targeted reactions due to their high purity levels.
Additionally, peptide vaccines allow preventative therapy for illnesses not caused by pathogens, including specific cancers. Advances in vaccine development include the development of multi-epitope vaccines that facilitate humoral and cellular immune responses.
Radio Theranostics uses low-penetration radiation in clinical applications like positron emission tomography (PET) to map disease progression and facilitate treatment. It utilizes molecular imaging using peptides alongside targeted radionuclide therapy to obliterate targeted cells while causing minimum undesirable effects.
The process’s main application is in treating cancer tumors. However, advances in peptide research hold immense potential for developing novel radio theranostics approaches to increase the range of radiation targets.
Peptide Assays are lab tests designed to detect peptide presence and concentration in biological samples. The peptides used in such tests function as biomarkers and are helpful in disease detection and diagnostics.
Besides screening for disease, peptide assays are instrumental in peptide and protein research and can detect allergens in skin sensitization. An example of a peptide assay is the enzyme-linked immunoassay (ELISA) test kit used to diagnose HIV, hepatitis, and other medical conditions.
Peptides play an invaluable role in biotechnology, medicine, and pharmacy, to improve disease detection, treatment, and management. Additionally, the numerous advantages associated with peptide synthesis position it as the future of drug discovery and development. However, further peptide research is necessary to develop techniques for efficiently producing unique, complex peptides.