Determination of Isoelectric Point of Recombinant Protein Drugs

Recombinant protein drugs refer to protein products derived from animals and plants and developed through biotechnology research. They have certain biological activity, and can prevent, treat and diagnose diseases in humans and animals. Compared to small molecule drugs, recombinant protein drugs have advantages of high activity, high specificity, and low toxicity, making them highly favoured by researchers. Currently, recombinant protein drugs have been widely used in various fields such as tumors, autoimmune diseases, metabolic diseases, aging diseases, and degenerative diseases. The charge heterogeneity is a key attribute of recombinant protein drugs, which has a significant influence on the stability, solubility, in vivo and in vitro biological activity, as well as the kinetic function of the drug. The first characteristic of the charge heterogeneity of recombinant protein drugs is the determination of the isoelectric point.

 

The isoelectric point refers to the pH value when a molecule does not carry a net charge or is electrically neutral on a statistical average. Accurately determining the isoelectric point is an effective means of identifying recombinant protein drugs, because the isoelectric point of a specific protein is fixed, which is related to the components and conformation of the protein. Common methods for determining the isoelectric point of recombinant protein drugs include precipitation method, spectrophotometry, and isoelectric focusing. The isoelectric focusing based on capillary electrophoresis has become a powerful tool for isoelectric point determination due to its short time consumption, high accuracy, and low sample usage.

 

Capillary isoelectric focusing (cIEF) uses the principle that the net charge of the protein is zero at the isoelectric point, and conducts acrylamide gel electrophoresis of the protein to be tested in a special buffer solution. This special buffer solution is an amphoteric electrolyte, which can form a continuous pH gradient in the gel. When the electrophoresis is completed, the pH corresponding to the position where the protein migrates is the isoelectric point of the protein.

 

MtoZ Biolabs provides customers with drug quality research services that comply with global pharmaceutical regulations. We can directly provide protein isoelectric point detection based on cIEF, and also provide a complete service including method establishment, validation, and subsequent sample detection.