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Peptide Modification Services
Peptide chemists have a myriad of approaches available to optimize lead peptide structures for activity, potency and the desired selectivity for the target of interest. Thus multiple modifications and/or longer-range structural features (e.g. cyclization) are often necessary to obtain the desired stability. For example, while gonadotropin releasing hormone (GnRH) already contains pyroglutamic acid at the N-terminus and a C-terminal amide, clinically used analogs contain a D-amino acid at position 6 in the middle of the peptide to stabilize the peptides to metabolism as well as modified C-termini (Fig.1).
Fig.1 Gonadotropin releasing hormone (GnRH) and examples of clinically used analogs.
Below is a list of our available modifications (include but not limited to the following):
Peptides can be modified at the N terminus. In general, some standard peptide moieties must be accessible in order to be modified: an N-terminal amino group, the amino group of Lys, the thiol group of Cys, the hydroxyl groups of Ser, Thr, and Tyr. Therefore, these modifications might increase the biological activity of a peptide and prevent degradation by enzymes.
The C-terminal of the peptide is synthesized as an amide to neutralize negative charge created by the C-terminal COOH. This modification is added to prevent enzyme degradation, to mimic native proteins, and in some cases to remove hydrogen bonding at the C-terminal of the peptides which may interfere with the assays.
The introduction of non-natural amino acids generates modifications in the secondary and tertiary structures of a peptide, and is used to further enhance the stability and activity of peptide sequences.
For PEG peptides, the PEG is usually attached to the peptide using standard amide bond formation but other linkage chemistry is possible as well (e.g. thiol-maleimide, oxime ligation, click chemistry). Thus, PEGylating your peptide may overcome many of the challenges for peptide drug candidates.
Fluorescence and dye labeled peptides have been developed for in vivo biomedical imaging, protein binding and localization studies. The large number of commercially available ﬂuorophores, many of them in the form of activated species ready for derivatization, has simpliﬁed the synthetic eﬀort required to obtain the modiﬁed peptides and increased the ﬂexibility of the designs.
Protein post-translational modifications (PTMs) are important in the study of biology and disease prevention and treatment, which can increase the functional diversity of the proteome by the covalent addition of functional groups or proteins, proteolytic cleavage of regulatory subunits, or degradation of entire proteins.
• Cyclic Peptides
Disulfide-rich cyclic peptides and their disulfide bonds often have exciting potential as leads or frameworks in drug discovery. It can improve the potency, rigidity, target selectivity, and stability of proteases and stabilize the secondary structure of peptides.
We can create the best custom labels for all your needs just about any custom labeling system that your operation requires. Throughout the years, Creative Peptides has created many custom solutions that have become a standard in our industry.
Peptides are often not sufficiently immunogenic to elicit an immune response alone. Synthetic peptides (1,000–3,000 Da), which are widely used to generate antibodies that can be made immunogenic by conjugation to a suitable carrier.
Protein and peptide (epitope) tags are widely used in protein purification and protein detection. Protein tags refer to those with more than a dozen of amino acids, for example, green fluorescent protein; peptide tags and epitope tags are used interchangeably, referring to the likes of FLAG, Myc epitope, and poly-histidine.
Creative Peptides is specialized in the peptide modification services, providing a confidential and efficient service at competitive prices. Every step of peptide synthesis is subject to Creative Peptides' stringent quality control. Typical delivery specifications include:
• HPLC chromatogram
• Mass spec analysis
• Synthesis report
• Certificate of Analyses
1. Letzel, T. (Ed.). (2011). Protein and Peptide Analysis by LC-MS: Experimental Strategies (No. 15). Royal Society of Chemistry.
2. Olsen, J. V., Macek, B., Lange, O., Makarov, A., Horning, S., & Mann, M. (2007). Higher-energy C-trap dissociation for peptide modification analysis. Nature methods, 4(9), 709.
3. Sewald, N., Hollweck, W., Mütze, K., Schierlinger, C., Seymour, L. C., Gaa, K.& Jakubke, H. D. (1995). Peptide modification by introduction of α-trifluoromethyl substituted amino acids. Amino Acids, 8(2), 187-194.