Protein characterization and identification play a critical role in drug discovery, development, and manufacturing, especially when it comes to determining the safety and efficacy of potential biological products. Although in recent years there have been many innovations and advancements in the analytical techniques used by biopharma companies to characterize and identify proteins, the process remains challenging, owing mostly to the breadth and complexity of protein expression.
Let’s take a closer look at what you need to know about protein characterization and identification.
Though proteins are built with just 20 amino acids, their functionality and structural characteristics can vary quite a bit from one complex molecule to another, helping to form thousands of distinct proteins within the human body. These proteins are built for a range of different jobs and functions – to respond to stimuli, to replicate DNA, to form antibodies, to provide structure within cells and tissues, and so on. Biochemists use protein characterization techniques as a way of profiling these long, polypeptide chains of amino acids in order to better understand their individual use and function.
Protein characterization is the process of analyzing an individual protein through separation and detection. The unique protein is then identified by the defining characteristics of its structure and function (i.e. molecular weight, composition, purity, activity, and so on). To do this, chemists must first isolate or extract the protein from surrounding cells using a range of appropriate purification techniques.
To begin analysis of the character of a protein, scientists first look at the primary, secondary, tertiary and quaternary structures of a protein.
Today, the scope of methods used for protein characterization and identification is fairly wide-ranging – from one-step procedures to large-scale productions.
For example, biochemists may select a sample to be fractionated, lyse the cells (break down or destroy the cell membrane) and then extract the sample through differential centrifugation. In this method, the purified supernatant is separated from the rest of the sample debris. Even after several passes in a centrifuge, the supernatant may still contain thousands of distinct proteins.
This process, known as the purification of the protein of interest, takes place only after the sample protein has undergone an additional separation technique. Chromatography, for example, is one of the most common technologies used in protein purification and has become central to the process.
After a protein has been highly purified and finalized, biochemists can begin their characterization, which involves identification of many variables that impact protein physicochemical property and structure including:
There are a range of different protein characterization techniques that can be used to detect, isolate and map the unique amino acids that make up a protein chain. These methods allow for separation based on a broad assortment of characteristic properties.
Advances in biotechnology and bioprocessing have created new pathways for researchers to study proteins. Biologics manufacturers must deeply understand their therapeutic proteins – from their structure, to their physicochemical properties, and their biological activity – in order to connect these learnings to clinical performance. This makes protein characterization critical to the biomedical research sector. Similarly, protein characterization methods and information have been applied to many aspects of drug development, formulation and treatments, and in creating diagnostic reagents used to detect and screen for diseases. Overall, identifying the different aspects of a protein and connecting that understanding to its clinical performance is central to successful product development.
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