Phosphorylated Peptides: Phosphorylation is among the most common post-translational modifications in nature, and in human cells at some point more than 30% of the proteins are phosphorylated. Phosphorylation, especially reversible phosphorylation, plays a significant role in controlling many cellular processes like signal transduction, gene expression, cell cycle and cytoskeletal regulation, and apoptosis. Deregulated phosphorylation causes various diseases, hence there is growing importance to analyze the phosphorylation state of proteins and peptides. Phosphorylation can be observed on various residues but most common phosphorylation targets are serine, threonine, and tyrosine residues (4), (5). Bachem has successfully manufactured many complex multi-phosphorylated peptides with modifications on serine, tyrosine and threonine residues.
Cyclic Peptides: Cyclic peptides are polypeptide chains wherein the ring structure is formed via a covalent bond between amino and carboxyl terminus, amino terminus and side chain, carboxyl terminus and side chain, or side chain and side chain. Cyclic peptides have several applications in medicine as they tend to be extremely resistant to digestion and, unlike their linear counterparts, can survive in the digestive track. As they are more ‘rigid’ than the open structures they may show enhanced affinity for their target receptors.
Figure-2: Phalloidin- an example for a complex cyclic peptide
They are attractive research targets and help in the engineering of peptides for the development of oral formulations. (6). Bachem has experience in synthesizing complex cyclic peptides and we would be pleased to offer custom synthesis for such compounds
PEGylated Peptides: The short half-life of peptides, their rapid clearance (within minutes of administration) by the kidneys or the mononuclear phagocyte system and their susceptibility to degradation by proteolytic enzymes is one of the biggest challenges in the development of peptide-based drugs. Chemical modification of the peptide using polyethylene glycol (PEG) can help to overcome the above mentioned drawbacks with minimal increase in manufacturing cost. PEG is a highly investigated polymer that is used in covalent modification of biopolymers like peptides. Once linked to a peptide, each PEG subunit becomes tightly associated with two or three water molecules, which have the dual function of rendering the peptide more soluble in water and enlarging its molecular structure. As the kidneys filter substances according to size, the addition of PEG prevents the premature renal clearance undergone by small peptides. PEG’s globular structure also acts as a shield to protect the peptide from proteolytic degradation, and reduces the immunogenicity of foreign peptides by limiting their uptake through the dendritic cells. Bachem offers the chemical synthesis of pegylated peptides from research quality, through development and the production of commercial lots as a cost-effective trade-off for a potential increase in bioavailability over the unmodified peptide (7).
Click Chemistry Peptides: Click chemistry is a broadly used tool to chemoselectively construct, complex peptides and is an efficient method to couple molecular fragments under mild conditions. Click chemistry reactions are highly efficient, wide in scope, stereospecific and offer an easy way to couple low- molecular fragments containing alkyne or azide functionalities. The Cu catalyzed alkyne-azide cycloaddition (CuAAC) click reaction works by “clicking” an alkyne-modified substrate with an azide-modified molecule forming a triazole link connecting the two units. Being highly chemoselective and stereospecific Click chemistry contributed to the accelerated development of peptide drugs (8). Bachem is proud to offer custom click chemistry for your research and development projects. We have the experience in the synthesis of complex peptides with high purity (9).
Hydrocarbon Stapled Peptides: High conformational instability of peptides leading to proteolytic cleavage and low bio-availability can be tackled via conformational stabilization of the alpha-helical structure. Hydrocarbon-stapled peptides are mini-proteins locked into their bioactive alpha-helical conformation through site-specific introduction of a chemical brace, an all-hydrocarbon staple. The synthesis protocol requires incorporation of α-alkenyl -α-methyl–amino acids allowing the ring-closing olefin metathesis (RCM) of the resulting resin-bound peptides. Bachem is pleased to offer this promising new modality of stapled alpha-helical peptides targeting a wide range of therapeutic areas. Get those special peptides that can enhance your peptide drug properties (affinity, protection against proteolytic degradation, robust cell penetration, and longer half-life) (10); (11); (12).
Branched Peptides: Branched peptides are used as antigens to produce antibodies, as toxin peptides for tumor targeting and for gene transfection. They are known to stimulate the immune system when used in the form of vaccines. They are used to act against a broad range of infectious diseases, (13) in the form of novel drugs, vaccines or carriers for gene therapy (14). Amphiphilic branched peptides are also used in packaging systems for drug delivery to overcome problems associated with lipid and viral based delivery systems (15). Although the synthesis of these peptides is challenging, Bachem has the expertise to come up with specific synthesis strategies in order to advance your project.
Stable Isotope-labeled Peptides: Bachem provides heavy isotope-labeled peptides to support novel innovation in pharmaceutical and biotechnology industry. Our stable isotope-labeled peptides are synthesized and purified under stringent conditions to obtain high purity. Such Labeled peptides are used in techniques such as ICAT (isotope coded affinity tags) and iTRAQ (isobaric tags for relative and absolute quantification). Stable isotopes are useful in the quantification of complex proteins and peptides at very low concentrations and for monitoring the relative abundance of proteins and peptides by mass spectrometry. They are used in molecular structure studies, elucidation of metabolic pathways, protein interactions, metabolism studies, metabolic research, diagnosis and much more. Bachem prepares peptides containing 15N, 13C and 2H (deuterium)-labeled amino acids according to your needs. They are non-radioactive and safe to use. (16); (17)
Dye Labeled Peptides: dye-labeled peptides have been used as powerful tools to investigate protein structures and relevant biological interactions such as receptor binding. The fluorophores can be incorporated at many positions (depending upon the need) before removing the protecting groups from the amino acids. Most of the fluorescent dyes are resistant to harsh deprotection conditions. Fluorescein isothiocyanate (FITC), carboxyfluorescein (FAM), carboxytetramethylrhodamine (TAMRA, 5 or 6 isomer or mixture of isomers), 7-methoxycoumarinyl-4-acetyl, aminomethylcoumarin, 5-(dimethylamino)naphthalene-1-sulfonyl, Dansyl, Bodipy are a few to mention in the series. Dye labeled peptides have found applications in medical diagnostics, especially in the field of cancer (18).
FRET Labeled Peptides: The principle of FRET (Fluorescent Resonance Energy Transfer) is commonly used with substrates for assaying protease activity and to investigate protein-protein interactions. In protein kinase assays, FRET can serve as a safe alternative to radioisotope labeling. (19).
Biotinylated Peptides: Biotin has a very high binding affinity for strepatavidin and avidin which is the basic principle behind the use of biotinylated peptides in numerous biochemical applications including immunoassays, histocytochemistry, and flow cytochemistry. Biotin can be covalently linked to either the N-terminus, C-terminus or to a lysine side-chain. For peptides that interact with large molecules like antibodies or macromolecules it is recommended to insert a spacer arm between the biotin group and the amino acid. (20), (21).
1. Thundimadathil, J. and Gangakhedkar, A., Improving stability of peptide drugs through chemical modifications, Chimica Oggi-Chemistry Today 32, 35-38 (2014)
2. Rodriguez, M. C. and Cudic, M., Optimization of physicochemical and pharmacological properties of peptide drugs by glycosylation, Methods Mol Biol 1081, 107-136 (2013)
3. Egleton, R. D., Mitchell, S. A., Huber, J. D., Palian, M. M., Polt, R. and Davis, T. P., Improved blood-brain barrier penetration and enhanced analgesia of an opioid peptide by glycosylation, J Pharmacol Exp Ther 299, 967-972 (2001)
4. McLachlin, D. T. and Chait, B. T., Analysis of phosphorylated proteins and peptides by mass spectrometry, Curr. Opin. Chem. Biol. 5, 591-602 (2001)
5. Hunter, T., Signaling–2000 and beyond, Cell 100, 113-127 (2000)
6. Craik, D. J., Chemistry. Seamless proteins tie up their loose ends, Science 311, 1563-1564 (2006)
7. Hamley, I. W., PEG-peptide conjugates, Biomacromolecules 15, 1543-1559 (2014)
8. Li, H., Aneja, R. and Chaiken, I., Click chemistry in peptide-based drug design, Molecules 18, 9797-9817 (2013)
9. Ahmad Fuaad, A. A., Azmi, F., Skwarczynski, M. and Toth, I., Peptide conjugation via CuAAC ‘click’ chemistry, Molecules 18, 13148-13174 (2013)
10. Verdine, G. L. and Hilinski, G. J., Stapled peptides for intracellular drug targets, Methods Enzymol. 503, 3-33 (2012)
11. Kim, Y. W., Grossmann, T. N. and Verdine, G. L., Synthesis of all-hydrocarbon stapled alpha-helical peptides by ring-closing olefin metathesis, Nat. Protoc. 6, 761-771 (2011)
12. Walensky, L. D. and Bird, G. H., Hydrocarbon-stapled peptides: principles, practice, and progress, J. Med. Chem. 57, 6275-6288 (2014)
13. Pini, A., Falciani, C. and Bracci, L., Branched peptides as therapeutics, Curr. Protein Pept. Sci. 9, 468-477 (2008)
14. Q. Leng and A.J. Mixson, Modified branched peptides with a histidine-rich tail enhance in vitro gene transfection, Nucleic Acids Res 33, e40 (2005)
15. Gudlur, S., Sukthankar, P., Gao, J., Avila, L. A., Hiromasa, Y., Chen, J., Iwamoto, T. and Tomich, J. M., Peptide nanovesicles formed by the self-assembly of branched amphiphilic peptides, PLoS One 7, e45374 (2012)
16. Aebersold, R. and Mann, M., Mass spectrometry-based proteomics, Nature 422, 198-207 (2003)
17. Gerber, S. A., Rush, J., Stemman, O., Kirschner, M. W. and Gygi, S. P., Absolute quantification of proteins and phosphoproteins from cell lysates by tandem MS, Proc. Natl. Acad. Sci. U. S. A. 100, 6940-6945 (2003)
18. Becker, A., Hessenius, C., Bhargava, S., Grotzinger, C., Licha, K., Schneider-Mergener, J., Wiedenmann, B. and Semmler, W., Cyanine dye labeled vasoactive intestinal peptide and somatostatin analog for optical detection of gastroenteropancreatic tumors, Ann. N. Y. Acad. Sci. 921, 275-278 (2000)
19. Shiosaki, S., Nobori, T., Mori, T., Toita, R., Nakamura, Y., Kim, C. W., Yamamoto, T., Niidome, T. and Katayama, Y., A protein kinase assay based on FRET between quantum dots and fluorescently-labeled peptides, Chem. Commun. (Camb.) 49, 5592-5594 (2013)
20. Winkler, D. F. and McGeer, P. L., Protein labeling and biotinylation of peptides during spot synthesis using biotin p-nitrophenyl ester (biotin-ONp).
Proteomics 8, 961-967 (2008)
21. Lee, B. S., Gupta, S., Krishnanchettiar, S. and Lateef, S. S., Capturing SDS-treated biotinylated protein and peptide by avidin functional affinity electrophoresis with or without SDS in the gel running buffer, Anal. Biochem. 336, 312-315 (2005)
What is your official job title at Bachem?
I’m Sales Manager Custom Synthesis; in charge of research grade peptides in France, South-Europe and Asia.
How long have you been with Bachem? Where did you work before Bachem?
I am with for Bachem for 5 years now. Prior to my Bachem time, I was working for a company dedicated to Diagnostic. I was project leader in charge of R&D for blood virus detection and I have been a customer to Bachem for over 10 years.
What is your academic background?
I’m chemist by education; I studied Organic Chemistry in Ecole Nationale Supérieure de Chimie de Mulhouse. Then I studied bio-organic chemistry with a Ph.D. dedicated to the molecular basis of contact dermatitis, this was the opportunity to synthesize modified-amino acid and to perform manual and automated solid phase peptide synthesis.
What do you like to do outside of work (interests, hobbies)?
I like to take self-defense classes and I enjoy spending my leisure time hiking and skiing.
What makes a perfect day for you?
At perfect working day brings positive feedback from our partners about our products and services.
What is your business motto?
“Always being reactive, efficient, flexible and valuable force of proposition”.
What do you like most about your job?
The thing I like most is to give satisfaction to our customers, to bring useful tools for the Research.
Do you like to communicate any key message to the reader?
Always keep in mind that the peptides we synthesize play a major role in worldwide research. Small research grade projects can become large GMP projects!
What is your preferred peptide?
I’m so proud when I think about one HCV patented peptide which is now on the market for the detection of Hepatitis C in sera in blood banks. I did participate to the development of this sequence and it was a big success!
I also like Phe-Leu-Orn-Arg-Ile-Ala-Asn = FLORIAN, my son’s name; another success story!
Thank you very much Stephanie.