Quality Control of Drugs and Analysis of Unknown Proteins

Shimadzu has introduced both PPSQ 30A and 33A Edman Sequencer models to the European market.

Edman degradation has been developed by Pehr Edman and is a longstanding established method whereby an amino acid is sequentially cleaved from the N-terminus of a protein, derivatised and separated via HPLC to determine its retention time. By comparing the retention times with those of standard amino acids, the N-terminal sequence can be determined.

Although in recent years various mass spectrometric methods have replaced Edman degradation for the identification of proteins, this technique is still very useful. More and more protein-based drugs are being developed, and particularly in these cases it is necessary to accurately determine the N-terminus for quality control.

In spite of longer analysis times, Edman degradation is reliable, robust and its results are easily interpretable. In addition, Edman degradation also enables unequivocal differentiation between isobaric amino acids such as isoleucine or leucine that have the same mass but different structure. Possible impurities can be more effectively determined and quantified via Edman degradation. Identification of proteins that are not included in databases can also be carried out very effectively via Edman degradation.

The PPSQ series operates under isocratic separation conditions leading to high reproducibilities. The operating costs are also clearly reduced as HPLC solvents can be recycled and the required reagents can be purchased all over Europe from WAKO Chemicals. Shimadzu’s extensive European service network is an additional reason for deciding to replace an existing system or to a acquire a new system.