Protein Isoelectric Point Determination Service

    Proteins are ampholytes that contain both positively and negatively charged functional groups. Their net charge is predominantly determined by the pH of the surrounding environment. When the pH of the external environment makes the acidic and alkaline dissociations in the protein molecule balance, i.e., the positive and negative charges carried by the molecule are completely canceled out, this particular pH is known as the isoelectric point (pI) of that protein. At the pI, the protein's surface charge is zero, resulting in minimal solubility. The pI is specific to each protein and depends on its composition and structure, making its accurate determination a crucial method for protein identification. Furthermore, the pI serves as a critical metric in various biochemical and proteomic analyses, including two-dimensional gel electrophoresis (2D-PAGE), X-ray crystallography, and liquid chromatography-mass spectrometry (LC-MS).


    Based on capillary isoelectric focusing (cIEF), MtoZ Biolabs offers precise determination of the pI of any protein. Compared to traditional slab gel methods, cIEF boasts advantages such as short runtime, high precision, and minimal sample consumption. This technology is applicable to a variety of amino acids, peptides, recombinant proteins, enzymes, monoclonal antibodies, and has been widely utilized in clinical analysis.



    Santhi, O. K. et al. Indo Am. J. P. Sci. 2021.
    Figure 1. Method for Determining Protein PI


    Sample Submission Requirements

    Protein sample concentration > 0.5 mg/mL, purity > 90%, minimum quantity not less than 50 pmol.



    In the technical report, MtoZ Biolabs will provide you with a detailed report, including:

    1. Experimental Procedures

    2. Relevant Data

  • • cIEF Protein Isoelectric Points Analysis Service

    The isoelectric point (pI) of a protein is closely related to its amino acid sequence and three-dimensional structure. The pI of a specific protein is fixed, thus allowing the study of structural and functional differences among different proteins by comparing their pIs. Accurate determination of the pI is an important aspect of characterizing the charge heterogeneity of bioproducts.

  • • IEF Protein Isoelectric Points Analysis Service

    Protein molecules are ampholytes. When the pH of the solution is adjusted so that the positive and negative charges on the protein molecules are equal, the protein molecules do not move towards either the positive or negative electrodes in an electric field. At this point, the pH of the solution is the isoelectric point (pI) of the protein. The isoelectric point of a protein is closely related to its amino acid sequence and tertiary structure, and the isoelectric point of a particular protein is fixed.

Submit Inquiry
Name *
Email Address *
Phone Number
Inquiry Project
Project Description *


How to order?


Submit Inquiry