Amino acids are life’s most important building block, playing crucial roles in most biological and chemical processes and enabling the development of various chemicals and materials. In modern research, short peptides and amino acid derivatives are increasingly used as working standards to increase the accuracy and reliability of experimental results. Peptide-based and amino-acid-based drugs are being increasingly used in therapeutic areas like cancer treatment. In light of these developments, this article explores the role of short peptides and amino acid derivatives as working standards in modern research and their advantages and challenges. But before focusing on that, let’s address an important question:
What are short peptides and amino acid derivatives?
Amino acids are organic compounds containing amino and carboxylic acid groups. While more than 500 amino acidunction normally. Short chains of amino acids are usually formed to make peptides, which then combine to form proteins. Peptides generally have 2-100 amino acid molecules; for exams have been detected in nature, the average human body generally needs only 20 amino acids to fple, the hormone insulin is a peptide comprising 51 amino acids.
How are short peptides different from rigid peptides?
Peptides are generally divided into two categories: short and rigid. The flexibility of the amino acid chain determines whether the peptide is categorised as a short or rigid peptide. Short peptides are generally more flexible and adaptable than rigid peptides. Their dynamic backbone allows the peptide to adapt various conformations depending on the environment around it. Furthermore, single bonds in short peptides can rotate freely, increasing their flexibility.
Because of their dynamic backbone and rotatable single bonds, short peptides cannot form rigid complexes like α helixes but are more susceptible to chemical substitutions and modifications. This affords short peptides with chemical versatility. Hence, short peptides can be tailored according to the research requirement. Consequently, they are used as working standards in research. As working standards, short peptides and amino acid derivatives offer various advantages.
Why are short peptides and amino acid derivatives used as working standards?
Before tackling this question, let’s address an even more important one:
What are working standards?
Working standards are chemicals used for calibration and performance verification of equipment. They are also used in repeatability, reproducibility and accuracy tests to determine the reliability of a particular analysis method. Working standards are not certified reference materials and do not emulate the same accuracy level as reference standards; hence, they are relatively cheaper.
Reference standards are commonly used in experiments where the standard for result accuracy, reliability and repeatability is stringent, e.g., when researchers want to report results. By contrast, working standards can be used when the standard is relatively less strict, e.g., when researchers want to conduct initial tests.
Having understood what working standards are and how they’re different from reference standards, let’s go back to why short peptides and amino acids are used as working standards. There are several reasons:
They are reliable.
As mentioned, short peptides and amino acid derivatives have been the focus of research for several decades. Hence, their chemical and physical properties have been well-characterised. Good-quality solutions of these compounds will almost always yield the same results. Therefore, they are used to calibrate instruments and validate protocols across different laboratories.
They are versatile.
Short peptides can be easily modified and synthesised because of their flexible backbone and side chains. Similarly, amino acid derivatives solubility, stability, and bioavailability can be tuned according to requirements. Researchers have introduced specific modification methods to tailor peptides and amino acid derivatives for particular applications. Consequently, they can be used as working standards in various experimental setups.
They are relatively easy to work with.
Short peptides and amino acid derivatives are stable under experimental conditions. They can be easily stored and handled, and no additional safety requirements or personnel training is required, making them easy to work with. They have less stringent storage requirements and do not spoil quickly, making them reliable for experimental work.
They are inexpensive.
Short peptides and amino acid derivatives have scalable manufacturing processes. Consequently, they can be synthesised cheaply and without too much financial investment. This also translates into the market cost of chemicals, and they are cheaper than other standards.
These advantages make short peptides and amino acid derivatives commonly used as working standards.
Application areas of short peptides and amino acids
Short peptides and amino acid derivatives are used as working standards in various fields:
Quality control in manufacturing
Short peptides and amino acid derivatives often serve as working standards during pharmaceutical manufacturing to ensure the purity and consistency of the product. They are also used in high-performance liquid chromatography, mass spectrometry, and other spectroscopic analyses to confirm the identification of the peptides produced.
Drug discovery and development
Short peptides and amino acid derivatives are used as standards to test the stability, efficacy and safety of new peptide-based pharmaceutical products. They are reliable and have defined physical properties, which makes comparison and confirmation easy.
Biosimilar development
Short peptides are used as a reference to compare the biological identity of the new biosimilar to that of the original product. The activity, stability, and structure of biosimilar and established drugs are compared to ensure equivalency.
Peptide library
During analysis, the analyte is often compared with a peptide library. This library is developed by using short peptides as benchmark compounds. They validate the screening process, and their activity is compared with the analyte's.
Industrial biotechnology
Peptides used in industrial processes are standardised using short peptides and amino acid derivatives. This comparison ensures consistency in their activity under industrial conditions, confirming whether they can be used for the process.
Challenges faced by short peptides and amino acid derivatives
While the use of short peptides and amino acid derivatives offers several advantages, their applications are limited by several challenges:
Stability challenges
While most short peptides and amino acid derivatives are stable, several are prone to hydrolysis when stored in aqueous solutions for a long time. Furthermore, some amino acid derivatives are prone to oxidation. These alter the structure, functionality and activity of short peptides and amino acid derivatives, resulting in inaccurate results.
Synthesis challenges
The synthesis of high-quality short peptides and amino acid derivatives is complex and has multiple complicated steps. This complexity increases the time required for synthesising every batch and the chances of errors. Consequently, short peptides and amino acid derivatives face purity concerns, which limits their use in experimental settings.
Bio-stability challenges
Short peptides, especially linear ones, are susceptible to enzymatic attack in biological settings. This limits their activity in vivo. Furthermore, some short peptides and amino acid derivatives also provoke immune responses in the human body, which limits their use in medicines and pharmaceutical products.
Analytical challenges
Some short peptides and amino acid derivatives exhibit inconsistent behaviour in analytical assays like mass spectrometry and HPLC. This can make results unreliable or challenging to read, especially when new analytes are being analysed. Furthermore, short peptides and amino acid derivatives have to interact with various compounds in biological settings (e.g., in blood, urine, or tissue samples), which can lead to signal suppression and inaccurate results.
Conclusion
Short peptides and amino acid derivatives are biological compounds that play considerable roles in various biological processes. Owing to their abundance, they have been widely studied. In recent years, they have been used as working standards in the pharmaceutical, chemical, and engineering fields due to their flexibility, low cost, high stability, versatility, and reliability. However, the use of short peptides and amino acid derivatives is still limited by various challenges, such as their complex synthetic procedure, susceptibility to hydrolysis and oxidation, low bio-stability and low reliability in biological matrixes. Thankfully, researchers are making considerable headways in overcoming these limitations, which is expected to enhance their use in various fields.
