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Peptide PEGylation

Peptides play a key role in the pharmaceutical industry and drug therapeutic development; however, their in vivo applications are sometimes limited due to fast degradation by proteases, poor solubility, antigenic responses, and glomerular filtration in the kidney. The covalent attachment of polyethylene glycol (PEG) chains to peptides is one approach that, in some peptide-PEG conjugates, to reduce immunogencity, improve solubility, and reduce renal clearance. Short (n = 2 to 20) monodispersed PEG chains can also be used as spacers or linkers between the peptide and other bio- or small molecules.

PEG chains for custom peptide synthesis

CPC Scientific can perform PEGylation modifications at various sites of a peptide. N-terminal PEGylation can be accomplished by direct PEG carboxylic acid coupling or native chemical ligation with PEG thioester and a cysteine residue in the peptide. C-terminal is more complicated, but can be achieved through a thiocarboxylic acid modification and sulfone-azide PEG reagent. Hydrazide modifications combined with a pyruvoyl PEG reagent is also a useful approach to C-terminal PEGylation. In addition to the N- and C-terminal, PEGylation is also possible at virtually any amino acid side chain bearing the appropriate functional group. In this context, three methodologies are often used for site-specific PEGylations:

  1. Click Chemistry, which takes place between an azide group of the PEG reagent and an alkyne group of the peptide, or vice versa.
  2. Sonogashira Coupling, which takes place between an iodophenyl group of the PEG reagent and an alkyne group of the peptide, or vice versa.
  3. Suzuki-Miyaura Coupling, with takes place between the iodophenyl group of PEG reagent and an aryl borinic acid group of peptide, or vice versa.
PEG monoethylene glycol
PEG2 diethylene glycol
PEG3 triethylene glycol
PEG750 Poly(ethylene glycol) methyl ether (average Mn 750)
PEG1000 Poly(ethylene glycol) methyl ether (average Mn 1000)
PEG2000 Poly(ethylene glycol) methyl ether (average Mn 2000)
PEG5000 Poly(ethylene glycol) methyl ether (average Mn 5000)
mono-dispersed PEGlyated Custom Peptides

Dvir, Hay, et al. "Atomic structure of the autosomal recessive hypercholesterolemia phosphotyrosine-binding domain in complex with the LDL-receptor tail." Proceedings of the National Academy of Sciences 109.18 (2012): 6916-6921.

PEGylated Custom Peptide Citations

"Two versions of the peptide L19K were synthesized by CPC Scientific (Sunnyvale, CA) consisting of the sequence DO3A- or NO2A-PEG4-GGNECDIARMWEWECFERK-CONH2, with a Cys-Cys disulfide bridge and polyethylene glycol (PEG) as a spacer between peptide and chelate."

1. Mastren, Tara, et al. "Cyclotron Production of High–Specific Activity 55 Co and In Vivo Evaluation of the Stability of 55 Co Metal-Chelate-Peptide Complexes." Molecular Imaging 14.10 (2015): 11-22.Learn More »

"Thrombin-sensitive reporter 1 (R1) was synthesized by CPC Scientific, with the sequence Biotin-PEG5kDa-Lys(5FAM)-Gly-Gly-DPhe-Pro-Arg-Ser-Gly-Gly-Gly-Cys, where PEG5kDa is 5 kDa poly(ethylene glycol)."

2. Warren, Andrew D., et al. "Disease detection by ultrasensitive quantification of microdosed synthetic urinary biomarkers." Journal of the American Chemical Society 136.39 (2014): 13709-13714.Learn More »

"L19K was synthesized by CPC Scientific and comprised the sequence NO2A-PEG4-GGNECDIARMWEWECFERK-CONH2, with Cys-Cys disulfide bridge and polyethylene glycol (PEG4) as a spacer between peptide and chelator."

3. Marquez, Bernadette V., et al. "Development of a radiolabeled irreversible peptide ligand for PET imaging of vascular endothelial growth factor." Journal of Nuclear Medicine 55.6 (2014): 1029-1034.Learn More »

"Synthesis was conducted at CPC Scientific Inc. Ac-Asp(OtBu)-Thr(tBu)-His(Trt)-Phe-Pro-Ile-Cys(Trt)-Ile-PhePEG3-Arg(Pbf)-Arg(Pbf)-Lys(Boc)-wang resin (2)… Ac-Asp-Thr-His-Phe-Pro-Ile-Cys-Ile-Phe-PEG3-Arg-Arg-Lys(BODIPY_TMR_C6)."

4. Skerratt, Sarah, et al. "Identification of a novel BODIPY minihepcidin tool for the high content analysis of Ferroportin (SLC40A1) pharmacology." MedChemComm (2016).Learn More »

"The structure of the new GE11 derivative (TA-GE11-DOTA) used to decorate the AuNPs is presented in Figure 4.4. TA-GE11-DOTA contains a PEG spacer between the GE11 amino acid sequence and the DOTA chelator, which has been introduced at the ε-amine group from one lysine. There are two more lysine residues to increase the water solubility of the conjugate and a terminal thioctic acid for attachment to the AuNPs surface. The compound was custom synthesized by CPC Scientific, which has confirmed its formulation and purity (> 95%) by ESI-MS and HPLC analysis... This BBN derivative (TA-BBN) contains a thioctic acid moiety at the N-terminal side of the peptide and was custom synthesized by CPC Scientific, which has confirmed its formulation and purity (> 95%) by ESI-MS and HPLC analysis."

5. Silva, Francisco França Alcântara Conceição. "Gallium compounds for the design of (nano) radiophamarceuticals." (2014).Learn More »

"Linear and cyclic targeting sequences of the peptides CCVVVT-EG 4 -GRGDSP-NH 2 (97%) (Cap-lRGD) and c[RGDfK(CCVVVT-EG 4 )] (96%) (Cap-cRGD) were purchased from CPC Scientific."

6. Ng, Quinn KT, et al. "Indium-111 labeled gold nanoparticles for in-vivo molecular targeting." Biomaterials 35.25 (2014): 7050-7057.Learn More »

"The peptides P20A (Ac-AAASGINAEWPLWPGEAGWGRLEGRRTYEAEI-NH 2 ) andbiotin-P20A (biotin-PEG4-AAASGINAEWPLWPGEAGWGRLEGRRTYEAEI-NH2 ) were synthesized by CPC Scientific."

7. Fu, Shushu, et al. "P20A inhibits HIV-1 fusion through its electrostatic interaction with the distal region of the gp41 fusion core." Microbes and Infection 17.9 (2015): 665-670.Learn More »

"The peptides, shown in Figure 1, were designed and synthesized. MPER (RRRNEQELLELDKWASLWNWFDITNWLWYIRRRR), TT peptide (FNNFTVSFWLRVPKVSASHLE), T10HE peptide (FNNFTVSFWLRVPKVSASHLE-PEG2-LWNWF-S5-ITN-S5-LWYIR-PEG2-KK), and T10E peptide (FNNFTVSFWLRVPKVSASHLEPEG2-LWNWFDITNWLWYIR-PEG2-KK) were purchased from CPC Scientific Inc. (Sunnyvale, CA, USA)."

8. Yu, Yang, et al. "10E8-like neutralizing antibodies against HIV-1 induced using a precisely designed conformational peptide as a vaccine prime." Science China Life Sciences 57.1 (2014): 117-127.Learn More »

Cysteine-terminated peptides (Q1 = 5FAM-GGPLGVRGKK(CPQ-2)-PEG2-C, CPC Scientific.."

9. Kwong, Gabriel A., et al. "Mathematical framework for activity-based cancer biomarkers." Proceedings of the National Academy of Sciences 112.41 (2015): 12627-12632.Learn More »

PEG azido peptide for Click Chemistry

Cyclo (-RGDfK) Azido-PEG4 (RGDP-011). This RGD-based peptide contains a Click-ready azide group and PEG4 spacer. It binds specifically and with high affinity to αvβ3 receptors on neovascular blood vessel sections of different major human cancers. The integrin α(IIb)β(3)-specific cyclic hexapeptide contains an Arg-Gly-Asp (RGD) sequence.