A Rare Case: An Old Technology Still Preferable over Newer Ones

Newer technologies normally surpass older methods, especially in today’s rapidly evolving biotechnology field. However, we here present you with an example of an old approach that stays relevant and survives year after year.

In 1950, the Swedish biochemist Pehr Edman announced a method that is still applied to this day. After being automated in 1967, the so-called Edman degradation spread widely and were being used all over the world. A simplified description of its application could be: To identify amino acids in small proteins known as peptides. Since 1950 great advances have been made in the field of biotechnology and protein research. This is also the case for methods, which analyze the amino acid content in peptides, with mass spectrometry being a particularly used method. However, Edman degradation is still applied despite its expensive materials and limited number of experienced users, since it offers several advantages compared to e.g. mass spectrometry. Larger proteins cannot be analyzed by Edman degradation, unless the protein is cleaved into smaller peptides of maximum 50 amino acids. This procedure is easily done and this expands the use of Edman degradation even more.

What you should know about Edman degradation

The start of the amino sequence is called the N-terminal. It often contains several amino acids that determines the protein’s proper location in the cell. The first amino acid, referred to as the N-terminal amino acid, is important for the likelihood of the protein being degraded. This likelihood should be as low as possible to ensure that the protein reaches its destination in the body.

During production of biopharmaceuticals containing small proteins, namely peptides, it is of interest to verify the amino acid sequence. The peptide is the active substance of the drug and must therefore be checked for the right structure to perform the intended function. N-terminal Edman degradation is especially useful for this purpose, since it does not damage the protein along the process. It is a cyclic procedure, which cleaves off amino acid residues one at a time. Afterwards, the actual sequence is compared to the expected sequence and thereby, it is possible to evaluate on the production process.

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