Chemical & Physical Analyses
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Chemical & Physical Analyses

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Physical testing determines the performance at the macro level, while chemical analysis focuses more on the materials at the micro-level, analyzing the chemical structure, element composition, and spectral characteristics of the material. Creative Peptides is not only an expert in the synthesis of various modified peptides but also provides a variety of peptide analysis services to support a variety of different applications.

Below is a list of our available Analyses Services (include but not limited to the following):

  1. Peptide identification

We have been long focused on optimizing our mass spectrometry technology platform. We have developed a comprehensive peptide identification pipeline, which processed with sample preparation, peptide separation and purification, followed by mass analysis.

  1. Net peptide content determination

Net peptide content are the major factors affecting variability between batches of peptides. The content of net peptide was determined by amino acid analysis (AAA) and elemental analysis (CHN). AAA only needs the least amount of peptides, while CHN consumes milligrams of peptides.

  1. Peptide Purity Determination

The purity of the peptide was determined by HPLC analysis, and the detection wavelength was 220nm, peptide bond absorbed here. The technique is used to separate, identify and quantify components in mixtures, such as target peptides and potential impurities.

  1. Peptide Molecular Weight Determination

Our peptide molecular weight analysis techniques include mass spectrometry (MS), to provide accurate measurements over a wide molecular weight range, with the least sample consumption, usually sub-picomole. We use different ionization (such as ESI and MALDI) and various detection methods, such as TOF, ion trap or quadrupole, depending on the properties of the peptide and the related detectability.

  1. Peptide Sequencing

Peptide sequence is an important basis for studying the biological function of peptides. However, the complete characterization of peptide, including post-translational modified (PTM), sequence mutation and mutation, is very challenging. We use database retrieval and de novo peptide sequencing to identify peptide.

  1. Peptide Charge identification (isoelectric point)

When pH=pI, the total surface charge of the peptide is zero, and the solubility of the peptide is the lowest. The isoelectric point of a specific peptide is fixed, which is related to the composition and conformation of the peptide, so the accurate determination of isoelectric point is often used as an effective method for the identification of peptides. Creative Peptides can accurately determine the isoelectric point of any protein based on capillary isoelectric focusing (cIEF). Compared with the traditional plate method, cIEF has the advantages of short-term efficiency, high accuracy, and small sample size.

  1. Peptide & Building Block Structure Confirmation

Creative Peptides uses NMR (Nuclear Magnetic Resonance) to determine and confirm the structure of peptides or building block for peptide synthesi. This principle is based on the different behaviors of atoms (such as 1H, 13C) in strong static and oscillatory magnetic fields, depending on their chemical environment. This technique is very suitable for precise structural identification of very small peptides and building blocks.

  1. Peptide Solubility Testing

In general, a challenging part of processing synthetic peptides is to determine the best solvent in which the peptides will be dissolved. Although some peptides are easily soluble in aqueous solution, a common problem encountered is that the solubility is very low or even insoluble, especially those with long hydrophobic amino acids. In order to achieve the best results, Creative Peptides provide services to test the solubility of peptides. According to the application of the target peptide, different organic solvents can be selected to measure the solubility by tsa.

  1. Peptide Stability Testing

Creative Peptides provides customized stability studies for your peptides. Equipped with a high-precision stabilization chamber, we propose different solutions, from simple short-term storage conditions to long-term solutions that meet ICH standards.

  1. Peptide Quantitation / Peptide Content Determination

Peptide therapy provides the highly selective benefits of biological agents, which can usually be synthesized and manufactured, and continue to gain more market share. In order to support the accurate measurement of peptide in drug development and quality control, peptide reference standards are needed for calibration in liquid chromatography, mass spectrometry or other analysis. The accurate determination of peptide content can be carried out by quantitative amino acid analysis.

  1. Amino Acid Composition

Peptides are single linear chains of many amino acids (of arbitrary length) linked together by amide bonds. Based on amino acid derivation technology and HPLC high performance liquid chromatographic analysis, Creative Peptides provides efficient and accurate analysis services for the amino acid composition of polypeptide drugs.

  1. Residual Solvent (e.g. DMF, Acetonitrile, DMSO, NMP…) Determination

Residual solvents from peptide synthesis and purification may be cytotoxic or lead to wrong results in biological applications. Creative Peptides established a GC method for the determination of ethanol, acetonitrile, ether and isopropanol in polypeptide drugs. FID was used as the detector and the content was calculated according to the external standard method.

  1. Residual Water Determination

Generally, lyophilized peptides are more stable at lower water content (< 3%) since high levels of residual moisture frequently lead to higher molecular mobility. In order to determine the exact composition of the lyophilized peptide probe, it is also necessary to analyze the amount of residual water. Creative Peptides was used to determine the residual water in peptides by gas chromatography.

  1. Residual Counter-Ion (e.g. TFA, HCl, HOAc) Determination

Because of their chemical properties, freeze-dried peptides may still contain counterions on protonated amino functional groups (N-terminal, arg,His,Lys, etc.). In order to determine the exact net amount of freeze-dried peptide samples, it is necessary to analyze the amount of residual counterions. The counterions in synthetic peptides were determined by ion chromatography.

  1. Disulfide bridges determination

Disulfide bond is a kind of post-translational modification formed between the sulfur atoms of two cysteine residues in the process of protein intracellular biosynthesis. Disulfide bonds play an important role in the process of protein folding, and they play an important role in the structure and function of proteins. Therefore, the analysis of disulfide bonds in proteins is of great significance to reveal the advanced structure and biological function of proteins. Creative Peptides provides services for drawing disulfide bond locations of unknown proteins and verifying disulfide bonds and folding structures of protein samples. The basic steps include peptide extraction, peptide separation and data analysis.

  1. Charge Variant Analysis

Charge heterogeneity may be caused by sequence variations (such as C-terminal lysine clamp), chemical degradation products (such as deamidation), and some post-modifications. We analyze the protein charge by ion exchange chromatography.

  1. Peptide Crystallization

The main purpose of peptide crystallization is to produce ordered crystals with uniform content, where they can have a reasonable and stable conformation and retain their natural structure and function. Creative Peptides has the ability to crystallize small peptides using advanced peptide crystallization techniques, especially for flexible peptides that do not have an ideal conformation.

  1. Enantiomeric Integrity

Except glycine, all the other amino acids contain at least one asymmetric carbon atom (Thr and Ile have two chiral carbon), so they all have chiral (chirality). Through the chiral amino acid analysis combined with mass spectrometry, the unexpected amino acid enantiomers in racemic peptides can be obtained, and the isomerization of amino acid chiral centers in the peptide can be accurately located, which lays a solid foundation for the screening of racemic peptide impurities and further rapid identification and quantification of trace racemic peptide impurities.

Our Advantages

  1. Highly skilled and committed scientific staff
  2. Corresponding cost-effective analytical services
  3. Analyses technical including LC-MS/MS, MALDI-MS, HPLC, AAA, NMR
  4. Mass spec analysis and HPLC chromatogram
  5. Free peptide consultation and design

References:
1. Singh, B. R. (2000). Infrared analysis of peptides and proteins. American.
2. Syka, J. E., Coon, J. J., Schroeder, M. J., Shabanowitz, J., & Hunt, D. F. (2004). Peptide and protein sequence analysis by electron transfer dissociation mass spectrometry. Proceedings of the National Academy of Sciences, 101(26), 9528-9533.
3. Geysen, H. M., Rodda, S. J., Mason, T. J., Tribbick, G., & Schoofs, P. G. (1987). Strategies for epitope analysis using peptide synthesis. Journal of immunological methods, 102(2), 259-274.

If you have any peptide synthesis requirement in mind, please do not hesitate to contact us at . We will endeavor to provide highly satisfying products and services.
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