Peptide Modifications

Structure Example


Stable isotope-labeled peptides including 13C, 15N, O18, and Deuterium

Stable Isotope-Labeled (SIL) Peptides

  • D-, 13C-, 15N-, or 18O-labeling capabilities


Biotin N-terminal peptide modification for assays with streptavidin

Peptides with N-Terminal Modifications 

  • Biotin, palmitoyl, PEG, dansyl, rhodamine, MCA, DNP, TAMRA, acetyl
CPC Scientific offers a wide range of C-terminal modifications

Peptides with C-Terminal Modifications

  • Aldehyde, chloromethyl ketone, alkyl amide, alcohol, hydrazide, thioester, para-nitroaniline
EDANS groups are a company modification to make FRET substrates

FRET & TR FRET Substrate Peptides

  • Mca/Dnp, Dabcyl/Edans, 5-FAM/ TQ2, 5-TAMRM/TQ3 or QSY7, Eu(III) or Tb(III)/Quenchers


glycosylation of peptides is an example of a post-translational modification

Glycopeptides and Glycated Peptides

  • O-linked and N-linked glycopeptides
  • alpha-, beta-Glc and beta-N-acetylgalactosamine (GalNAc)
  • Glucose: Ser(beta-D-GlcNAc), Thr(beta-D-GlcNAc, Asn(beta-D-GlcNAc), etc.
  • Galactose: Ser(alpha-D-GalNAc) and Thr(alpha-D-GalNAc) (Tn Antigens)
  • Ser(Gal-beta(1-3)GalNAc) and Thr (Gal-beta(1-3)GalNAc) (TF Antigens)
  • Mannose: Ser(alpha-D-ManNAc), Thr(alpha-D-ManNAc, Ser(alpha-D-Man), Thr(alpha-D-Man)
Positive charges help peptides penetrate cell membranes

Cell-Penetrating Peptides

  • TAT (transactivated-transcription) derivatives, penetratin, and transportan
  • Beta- and gamma-amino acids
Conjugation of DOTA groups to peptides to chelate metal ions

Chelating Peptides

  • DOTA (1,4,7,10-tetraazacyclododecane-N,N,N,N-tetraacetic acid)
  • NOTA (1,4,7-triazacyclononane-N,N,N-triacetic acid)
  • TETA (1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid)
  • DTPA (diethylenetriaminepentaacetic acid)
  • IDA (Iminodiacetic acid)
Cyclization can increase the bioavailability of peptides

Cyclic Peptides

  • Cys-Cys, Pen-Cys, and Pen-Pen cyclizations
  • Amide bond cyclizations
  • Head-to-tail, sidechain-to-sidechain, head-to-sidechain, sidechain-to-tail
  • Backbone-to-backbone, sidechain-to-backbone, backbone-to-sidechain, head-to-backbone, backbone-to-tail
farnesyl-labeled peptides

Farnesyl & Geranyl

Hydroocarbon staples can stabilize helical structures in peptides

Hydrocarbon-Stapled Peptides

  • i, i+3; i, i+4; and i, i+7
  • Double staple and Stitched staple peptides
lipid-peptide conjugates can help peptides anchor into cell membranes


  • NH-, S- and O-palmytoyl, myristyl, octanoyl, and stearyl

Main Chain Modified Peptides

  • N-Methylation, ester bond & reduced amide bond (CH2 NH)
Branched peptides can increase pepitde immunogenicity


  • Multiple Antigenic Peptide System
  • 2-branch, 4-branch, and 8-branch available
  • Custom branching motifs

Multiple Disulfide Bond Peptides

  • Peptide toxins (Apamin, Charybdotoxin, Chlorotoxin, omega-Conotoxins)
  • Defensins (alpha-Defensin 6, beta-Defensin-1-4, Defensin HNP-1 and HNP-2
  • Agouti-related Protein (AGRP) (87-132)
  • Custom cyclization motifs
pegylation of peptides can increase solubility and bioavailability

PEGylated Peptides

  • PEG spacers and PEG carriers
  • Mini-PEG1 (8-Amino-3,6-dioxaoctanoic acid)
  • Mini-PEG2 (12-amino-4,7,10-trioxadodecanoic acid)
  • Mini-PEG3 (15-amino-4,7,10,13-tetraoxapenta-decanoic acid)
  • Custom PEG moieties

Peptides for Click Chemistry Work

  • Peptide conjugation (dyes, PEG, radioligands, chelating molecules), cyclization, dimerization.
  • Ready-to-Click peptides
  • Copper-free click chemistry available

Dye-Labeled Peptides

  • Cy3 and Cy5 equivalent, Dabcyl, 5-FAM, 5-TAMRA, Edans, FITC, AMC, AFC, pNA, Uniblue A, Alexa Fluor, Tide Fluor and quencher

Peptide Libraries

  • PEPscreen® custom peptide libraries
  • Purified and unpurified
  • Alanine scanning, truncation, random, and positional scanning libraries




  • Custom peptide-aminoluciferin substrates


  • Phosphoserine, phosphothreonine, and phosphotyrosine
  • Phosphotyrosine mimic Pmp (phosphonomethylene phenylalanine)
  • Multiple sites

Rhodamine 110 Peptides

  • Minimal autofluorescence interference
  • Enzyme substrates, caspases, and custom sequences

Sulfated Peptides

  • Tyrosine, serine, and threonine O-sulfation
  • Experts in handling unstable sulfated peptides


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