Peptide Modifications
Over 300 modifications; Free amidation and acetylation
Includes Biotin, FITC, PEGylation, methylation, disulfide bonds
KLH, BSA, OVA conjugations
Custom Peptide Modifications
The peptide modification services at GenScript offer a wide range of modifications to meet any research need. These modifications can improve overall peptide stability, alter structure to better understand biological function, or enhance immunogenicity for antibody development and production. In addition to a variety of terminus and internal modifications, GenScript's services include peptide labeling and conjugations for imaging and detection needs.
For a list of our available modifications, select the modification options below:
-
| 5-FAM |
BSA (-NH2 of N terminal) |
Hexanoic acid |
PEN |
| 5-FAM-Ahx |
CBZ |
HYNIC |
Stearic acid |
| Abz |
Dansyl |
KLH (-NH2 of N terminal) |
Succinylation |
| Acetylation |
Dansyl-Ahx |
Lauric acid |
TMR |
| Acryl |
Decanoic acid |
Lipoic acid |
|
| Alloc |
DTPA |
Maleimide |
|
| Benzoyl |
Fatty Acid |
MCA |
|
| Biotin |
FITC |
Myristoyl |
|
| Biotin-Ahx |
FITC-Ahx |
Octanoic acid |
|
| BOC |
Fmoc |
OVA (-NH2 of N terminal) |
|
| Br-Ac- |
Formylation |
Palmitoyl |
|
-
| AFC |
MAPS Asymmetric 2 branches |
| AMC |
MAPS Asymmetric 4 branches |
| Amidation |
MAPS Asymmetric 8 branches |
| BSA (-COOH of C terminal) |
Me |
| Bzl |
NHEt |
| Cysteamide |
NHisopen |
| Ester (OEt) |
NHMe |
| Ester (OMe) |
OSU |
| Ester (OtBu) |
OVA (-COOH of C terminal) |
| Ester (OTBzl) |
p-Nitroanilide |
| KLH (-COOH of C terminal) |
tBu |
-
{d-ALA}
Alanine |
{NVA}
Norvaline |
{pTYR}
Phosphorylation (TYR) |
{Lys(biotin)}
Biotin Lysine |
{D-2-Nal} |
{L-4-Pal} |
{Mini-PEG1} |
{PEG2}
NH2-(PEG)2-CH2COOH |
{d-ARG}
Arginine |
{d-NVA}
Norvaline |
{gamma-GLU}
Gamma-GLU |
{Cys(Acm)}
Cysteine (Acm) |
{D-3-Pal} |
{Lys(5-FAM)} |
{Met(O)}
Methionine sulfoxide |
{PEG6}
NH2-(PEG)6-CH2CH2COOH |
{d-ASN}
Asparagine |
{ORN}
Ornithine |
{d-gamma-GLU}
D-Gamma-GLU |
{Cys(tBu)}
Cysteine (tBu) |
{D-4-F-Phe} |
{Lys(Dansyl)} |
{Met(O)2}
Methionine sulfone |
{PEG11}
NH2-(PEG)11-CH2COOH |
{d-ASP}
Aspartic Acid |
{d-ORN}
Ornithine |
{CIT}
Citrulline |
{d-1-NAL}
(D) 1-Nal |
{D-4-I-Phe} |
{Lys(FITC)} |
{Cpg}
Cyclopentylglycine |
{PEG12}
NH2-(PEG)12-CH2CH2COOH |
{d-CYS}
Cysteine |
{PEN}
Penicillamine |
{nme-ALA}
N-methylated ALA |
{L-1-NAL}
(L) 1-NAL |
{D-4-NO2-Phe} |
{Lys(Me)} |
{Pra}
Propargylglycine |
Dab(Dnp) |
{d-GLU}
Glutamic Acid |
{d-PEN}
Penicillamine |
{nme-ILE}
N-methylated Isoleucine |
{d-2-PAL}
(D) 2-PAL |
{D-4-Pal} |
{Lys(Me2)} |
{Tic}
1,2,3,4-Tetrahydroisoquin
oline-3-carboxylic acid |
Dap(Dnp) |
{d-GLN}
Glutamine |
{d-PHE}
Phenylalanine |
{nme-LEU}
N-methylated Leucine |
{L-2-PAL}
(L) 2-PAL |
{D-Beta-Asp} |
{Lys(Me3)} |
{Sec}
Selenocysteine |
Dpa |
{HCY}
Homocysteine |
{d-PRO}
Proline |
{nme-PHE}
N-methylated Phenylalanine |
{d-4-CL-PHE}
(D) 4-CL-PHE |
{D-Cha} |
{Lys(TMR)} |
{Se-Met}
Selenomethionine |
Lys(Dde) |
{d-HIS}
Histidine |
{d-SER}
Serine |
{nme-VAL}
N-methylated Valine |
{L-4-CL-PHE}
(L) 4-CL-PHE |
{D-Chg} |
{NMe-Asp} |
{Lys(N3)}
Azido-Lysine |
Lys(ivdde) |
{HSE}
Homoserine |
{d-THR}
Threonine |
{nme-SER}
N-methylated Serine |
{ABU}
Abu |
{D-Cit} |
{NMe-Glu} |
{Beta-HomoLeu}
Beta-HomoLeucine |
Oic |
{d-HSE}
Homoserine |
{d-TRP}
Tryptophan |
{nme-THR}
N-methylated Threonine |
{AIB}
Aib |
{Dab} |
{NMe-Nle} |
{Cys(Cam)}
Carboxyamidomethy
lated Cysteine |
Pip |
{d-ILE}
Isoleucine |
{d-TYR}
Tyrosine |
{nme-TYR}
N-methylated Tyrosine |
{MPA}
Mpa |
{Dap} |
{NMe-Nva} |
{Arg(Me)}
Methylation at the side chain of Arginine |
Tle |
{d-LEU}
Leucine |
{d-VAL}
Valine |
{alpha-ABA}
Alpha Amino-Butyric Acid |
{HYP}
Hydroxy Proline |
{L-2-Nal} |
{Phg} |
{ADMA}
Arg(Me)2 asymmetrical |
|
{d-LYS}
Lysine |
{pGLU}
Pyroglutamate |
{Beta-Asp}
Beta-ASP |
{Lys-Ac}
Acetylation at the side chain |
{L-3-Pal} |
{Ser(octanoic-acid)} |
{SDMA}
Arg(Me)2 symmetrical |
|
{d-MET}
Methionine |
{Lys(Dnp)}
Dinitrobenzylation (LYS) |
{Ac-LYS}
Acetylation at alpha amine group |
{Cha} |
{L-4-F-Phe} |
{d-HCY}
Homocysteine |
{Beta-Ala}
Beta-Alanine |
|
{NLE}
Norleucine |
{pTHR}
Phosphorylation (THR) |
{2-Me-ALA}
2-Methyl Alanine |
{Chg} |
{L-4-I-Phe} |
{d-pGLU}
Pyroglutamate |
{GABA}
4-Aminobutyric acid |
|
{d-NLE}
Norleucine |
{pSER}
Phosphorylation (SER) |
{nme-GLY}
N-methylated Glycine |
{D-2-Me-Trp} |
{L-4-NO2-Phe} |
{nme-MET}
N-methylated Methionine |
{Ahx}
6-amino-hexanoic acid |
|
-
| Arg(13C6,15N4) |
| Ile(13C6,15N) |
| Leu(13C6,15N) |
| Lys(13C6,15N2) |
| Val(13C5,15N) |
-
| 1-Pyrenemethylamine HCL |
FITC (N-Terminal) |
| 5-FAM (N-Terminal) |
FITC-Ahx (N-Terminal) |
| 5-FAM-Ahx (N-Terminal) |
Glu(EDANS)-NH2 |
| Abz (N-Terminal) |
MCA (N-Terminal) |
| Abz/DNP |
MCA/DNP |
| Abz/Tyr (3-NO2) |
Quenched fluorescent peptide |
| DABCYL |
Tyr (3-NO2) |
| DABCYL/Glu(EDANS)-NH2 |
TMR |
| Dansyl (N-Terminal) |
AMC |
| Dansyl-Ahx (N-Terminal) |
|
| EDANS/DABCYL |
|
-
| BSA (-COOH of C terminal) |
| BSA Conjugation on cysteine |
| KLH (-NH2 of N terminal) |
| KLH Conjugation on cysteine |
| OVA (-COOH of C terminal) |
| OVA (-NH2 of N terminal) |
| OVA Conjugation on cysteine |
-
| MAPS |
PEGylation |
Cyclic modifications |
Disulfide Bridges |
Other |
| MAPS Asymmetric 2 branches (C-Terminal) |
Mini-PEG1 |
Head to tail Cyclic |
Disulfide Bridge |
BOC |
| MAPS Asymmetric 4 branches (C-Terminal) |
Mini-PEG2 |
|
Double Disulfide bridge |
tBu |
| MAPS Asymmetric 8 branches (C-Terminal) |
{PEG2}
NH2-(PEG)2-CH2COOH |
|
Mono Disulfide bridge |
Succinylation |
| |
{PEG6}
NH2-(PEG)6-CH2CH2COOH |
|
Triple Disulfide Bridge |
Me |
|
{PEG11}
NH2-(PEG)11-CH2COOH |
|
|
p-Nitroanilide |
|
{PEG12}
NH2-(PEG)12-CH2CH2COOH |
|
|
p-Nitroanilide |
1. Amidation and Acetylation
If the peptide is from an internal sequence of a protein, terminal amidation (C-terminus) or acetylation (N-terminus) will remove its charge and help it imitate its natural structure (amide, CONH2). In addition, this modification makes the resulting peptide more stable towards enzymatic degradation resulting from exopeptidases.
2. Biotin and FITC
For C-terminal labeling of biotin, a Lys residue is added to the C-terminus of the peptide. Biotin is then attached to the lysine side chain via amide bond. The positive charge of the lysine is then removed.
Fluorescein isothiocyanate (FITC) is an activated precursor used for fluorescein labeling. For efficient N-terminal labeling, a seven-atom aminohexanoyl spacer (NH2-CH2-CH2-CH2-CH2-CH2-COOH) is inserted between the fluorophore (fluoroscein) and the N-terminus of the peptide.
3. Disulfide Bridge
Peptide cyclization can be achieved through creating disulfide bridges between cysteine residues on the peptide. This is a challenging practice for peptide containing multiple cysteine residues due to random formations of disulfide bridges between them. GenScript is able to build disulfide bridges between cysteine at specified positions. We are able to introduce up to three customized disulfide bridges on one peptide.
4. Phosphorylation
Phosphopeptides can assist in the investigation of the influences of phosphorylation on peptides and protein structure and in the understanding of regulatory processes mediated by protein kinases. GenScript has successfully synthesized numerous serine-, threonine-, and tyrosine-phosphopeptides. For peptides containing one or more of these hydroxy-amino acids, selective phosphorylation can be achieved by orthogonal protection or by Fmoc-protected phosphorylated amino acids.
5. Methylation
The methylation of proteins has been established as an important modification that helps regulate cellular functions such as transcription, cell division, and cell differentiation. Post-translational N-methylation usually occurs on lysine or arginine sidechains. Peptides that represent methylated proteins are useful for protein-protein interaction studies or structural determination by x-ray crystallography. GenScript can synthesize peptides containing mono-, di-, and tri-methylated lysines at >98% purity, as well as other methylation combinations.
6. BSA, KLH, OVA Conjugation
Peptide antigens are often too small to generate significant immune responses on their own. To solve this problem, these peptides are conjugated to bigger carrier proteins, such as bovine serum albumin (BSA), ovalbumin, or keyhole limpet hemocyanin (KLH). One of the advantages of KLH is that it does not interfere with ELISA or western blotting because it is not used as a blocking reagent. One common means of conjugation method is the maleimide method, which couples the cysteine residue of the peptide to the carrier protein. To perform this conjugation, one cysteine residue is added to the N- or C-terminus of the peptide so that it may be linked to the carrier protein.
Note: KLH is a large (MW = 4*105 to 1*107) aggregating protein. Because of its size and structure, its solubility in water is often limited, giving solutions and mixtures a cloudy appearance. This does not affect immunogenicity and the turbid solution can be used for immunizations. To avoid further confusion, we'll ship the peptides as solutions chilled with blue ice if precipitates appear after conjugation.
7. PEGylation
PEGylation is the covalent conjugation of macromolecules (antibody, peptide, etc.) with polyethylene glycol (PEG), polymers that are nonionic, nontoxic, biocompatible and highly hydrophilic. The PEGylated macromolecules have enhanced therapeutic properties due to their increased solubility (for hydrophobic drugs) and bioavailability, masked antigenicity for minimum immune response in host, prolonged circulatory time within host through reduced renal clearance.
8. Isotope Labeling
For NMR measurement, we can label peptides with stable nonradioactive isotopes. Peptides labeled with 2H, 15N, 13C, or both 15N and 13C can be synthesized for convenient detection in research. Please submit your sequence and request for a customized labeling of your peptides.
9. MAPS
Multiple antigen peptide application is one potent way to produce high-titer anti-peptide antibodies and synthetic peptide vaccines. This system utilizes the α- and ε-amino groups of lysine to form a backbone to which multiple peptide chains can be attached. Depending on the number of lysine tiers, different numbers of peptide branches can be synthesized. This eliminates the need to conjugate the antigen to a protein carrier.
Delivery Specifications
All peptide synthesis is subject to GenScript's stringent quality control. The typical delivery consists of lyophilized peptide of the required sequence, purity, and quantity and associated QC reports.
Quotations and Ordering
For quotations, please use our Secure Instant Online Quotation/Order system. However, you may also contact us by email, phone (1-732-885-9188), fax (1-732-210-0262), or via our Secure Messaging System.
Please use our online ordering system and either a PO (Purchase Order) or credit card to receive GenScript's fastest service. For batch order, please download and complete Standard Peptide Batch Order Form and email it to peptide@genscript.com. Our customer service representatives are available 24 hours, Monday through Friday to assist you.
We accept POs and major credit cards (
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