The Most Comprehensive Peptide Modifications

peptide-modification

Peptide modification is mainly for the main chain structure and the side chain groups of the peptide.It can change the physical and chemical properties of peptide by modification and can optimize their effective utilization in organisms.Modified peptides are widely used in peptide drugs, immunology, diagnostics, biocatalysis, modified antibodies and peptide reagents study.


Omizzur now provide most comprehensive peptide modifications for different research purpose.All custom peptide and modification services includes:

HPLC Analysis

Mass Spectrometry

Certificate of Analyses

Additional Qc services: Amino acid analysis | Solubility test /TFA | Endotoxin removal | Free peptide subpackage


Our peptide modification services include but are not limited to the following items:

N-terminal Modifications 

The N-terminal peptide is much more closer to the natural protein, the N-terminal modification may increase the biological activity ,stability of the peptide, also prevent the degradation by enzyme etc.


AcetylationCBZ BenzyloxycarbonylBoc Tertbutoxycarbonyl
MaleimideForFormylationFmoc9-Fluorenylmethyloxycarbonyl
Myristic acidFatty acidThioester
Palmitic AcidStearic acidCaprylic acid
SuccinylationLauric acidN-Methyl
BiotinAlkylaminemPEG
ThioesterDansyl/DabcylMpa
TosTosylationPyrPyroglutamylFluorescent dye

C-terminal Modifications

The c-terminal is the position of the connecting resin, in many times the solid-liquid phase two-step operation is required.C-terminal is modified by amidation normally which can removes the charge form the C-terminus of peptide.The C-terminal amides without charge are more closer to natural proteins.

By C-terminal modifications it can improve the stability of the peptide ,or prolongs their shelf life and also be used to produce substrates in enzymatic studies.


AmidationAMC7-amino-4-methylcoumarinylAFC7-amino-4-(trifluoromethyl)-2-benzopyrone
CMK/FMKChloro(fuoro)-methylketonesp-NitroanilideCysteamide(Mercaptoacetamide)
MAPs2/4/8 branchesEster (OMe/ OEt/OtBu/Obzl)TBzl
BSAOVAKLH
NH2NHMeNHEt
NHisopenNHPhtbu

Special Amino Acids  


Special amino acids and their derivatives are important tools for setting peptide sequences.By adding special amino acids, we can enhance the affinity, selectivity and stability of peptide drug leads.Another application is to use unnatural amino acids to induce or stabilize the secondary structures of peptide.


Omizzur has extensive experience in the application of specially modified amino acids to polypeptide synthesis
including:D-amino acids,unnatural amino acid,phosphorylation,sulfonation,methylation etc.


D-amino acidsUnnatural amino acidPhenylalanine derivatizationTyrosine derivatization
D-Ala
D-Asp
D-Thr
D-Leu
D-Asn
D-Ile
D-Met
D-Cys
D-Pro
D-Phe
D-Glu
D-Trp
D-Val
D-Ser
D-Alloile

Abu
Aib
DapOrn
Nal
NvaPal
Pra
PenTle
Met(O)
BpaCit
Dab
ChgHyp
Phg
ChaHArg
HSer
Beta-homo-amino acids
Phe(4-Cl)
Phe(2-Cl)
Phe(4-CN)
Phe(3-Cl)
Phe(4-Br)
Phe(3,4-DiCl)
Phe(4-F)
Phe(4-Me)
Phe(4-NH2)
Phe(4-NO2)
Tyr(Me)
Tyr(3-NO2)
Tyr(3-Cl)
Tyr(3-F)
Tyr (3,5-DiCl)
Tyr(3-I)
Tyr (3,5-DiF)
Methylation
Phosphorylation
SulfonationDinitrobenzoylation
Lys(Me)
Lys(Me2)
Orn(Me)
Orn(Me3)
Trp(2-Me)
His(1-Me)
Arg(Me2)
(Symmetry/asymmetry)
pSer
pThr
pTyr
Tyr(SO3H2)
Ala(SO3H2)
Lys
Lys (Me2)

Fluorescence/dye Labeling  


Reactive fluorescent dyes are commonly used to label proteins, nucleic acids and other biomolecules for life science applications, including fluorescence microscopy, flow cytometry, FISH, FRET, receptor binding analysis and enzyme analysis.

 

Fluorescein can be directly connected with the N-terminal of peptide, or with the side chain of lysine (or cysteine) at the C-terminal, or with other positions that can be connected.We recommend N-terminal modification, because the peptide is synthesized from C-terminal to N-terminal, the N-terminal modified peptide is just another step on the basis of conventional synthesis. On the contrary, C-end decoration is often more complicated.


FITCN-terminal5-FAM5-Carboxyfluorescein5(6)FAM5,6-carboxyfluoresceine
AMC (7-amino-4-methylcoumarinyl)Rhodamine B5-TAMRA
NBD (7-nitrobenz-2-oxa-1, 3-diazole)BiotinAMC/MCA
Cy3/Cy5DansylEDANS
HYNICDTPAAbz

Peptide Cyclization  


Since cyclic peptides tend to be more stable than linear peptides, they have a strong resistance to the digestive system, can survive in the digestive tract and show a stronger affinity for target receptors,which been attracted much attention In biotechnology and pharmaceutical industry. Cyclization is the most direct way to synthesize cyclic peptides, especially those with larger structures.Aurora have rich experience in Head to tail cyclization,Side chain cyclization,Single or multiple disulfide bridges,so on. 

Head to tail cyclizationSide chain cyclizationDisulfide bridgesOthers
•Amide cyclic(end,side chain)

•Lys side chain

•Orn side chain

•Glu side chain

•Mono disulfide bridg

e•Double disulfide bridge

•Triple disulfide bridge

•Thioester cyclic

•Ester bond

•Se-Cys cyclic

•Lactone cyclic

Atom Linker  


We insert a linker between the peptide and the marker.The commonly used hydrophobic link is amino-acetic acid (Ahx) and hydrophilic link can be polyethylene glycol (PEG). it can improve the solubility, protect the peptide from being destroyed by enzyme, and improve the half-life of biological activity. 

Beta-Alanine4-Aminobutyric Acid (GABA)5-Aminovaleric Acid (Ava)
(2-Aminoethoxy) acetic acid (AEA)Aminohexanoic acid (Ahx)12-amino-dodecanoic acid
3-Amino-3-(2-nitrophenyl)propanoic acid (ANP Linker)Mini-PEGPEG(mPEG 2000,3000,5000)

Peptide Conjugates  

The molecular weight of peptide antigen is too small to generate significant immune response. To solve this problem, peptides should be conjugated to large proteins carrier such as Keyhole Limpet Hemocyanin (KLH), Bovine Serum Albumin (BSA) or Ovalbumin (OVA).

KLH(Keyhole limpet hemocyanin) BSA(Bovine serum albumin ) OVA(Ovalbumin) 

•N terminal

•Cysteine

•C terminal

•Cysteine

•C terminal

•N terminal

•Cysteine

Multiple Antigenic Peptide  

Multiple antigenic peptides (MAP) is an effective method to produce high titer peptide antibody and peptide vaccine. MAPs are peptides that are branched artificially.According to the number of lysine, multiple antigenic peptides with different number of side chains can be synthesized so that the antibody with high titer and affinity can be produced without coupling the antigen to the carrier protein and also can increase their immunological responses.

MAPS
Asymmetric 2 branches Asymmetric 4 branches Asymmetric 8 branches  

Quenched Fluorescent Peptide(FRET peptide)

Peptide(FRET peptide)Fluorescence resonance energy transfer (FRET) is a non-radiative energy transition that transfers the energy of donor excited state to that of acceptor excited state through the electric dipole interaction between molecules.This process is non-radiative without the participation of photons.This analytical method has the advantages of rapidity, sensitivity and simplicity which make FRET peptides are widely used as suitable substrates in enzyme studies. 

EDANS with DABCYLAbz with Tyr (3-NO2)
Mca with DnpFAM with Dabcyl

Other Modifications

Isotope labelingGlycosylationp-Nitroanilide

•Arg(13C6,15N4)

•Ile(13C6,15N)

•Leu(13C6,15N)

•Fructose

•Glucose

•Mannose