Custom peptides synthesis
Lactam Ring Cyclic Peptides
We manufacture lactam-cyclized peptides also known as amide-bond cyclic peptides, to form head-to-tail or side-chain amide linkages between amine (NH2) and carboxyl (COOH) groups on the peptide N or C-terminus and/or side chains of Lys, Glu, Asp.
Available in Research and GMP grades.
Cyclization configurations
The primary ligation approaches to synthesize lactam cyclic peptides are
head-to-tail, side-chain-to-side-chain, head-to-side-chain, and side-chain-to-tail,
depending on the location of the functional groups within the peptide sequence.
- Occurs between N-terminus to C-terminus.
- Via Amide bond formation (lactamization).
- Most frequently used cyclization conferring greater stability.
Occurs between N-terminus and an internal COOH
(e.g. the ß-COOH-group of Asp or γ-COOH-group of Glu).
Occurs between internal NH2s and C-terminus
(e.g. the ε-NH2–group of Lys).
Occurs between Side chain of Lysine (ε-NH2–group of Lys)
to Aspartic or Glutamic acid (γ-COOH-group).
Featured Citations
Design of peptide-based PAC1 antagonists combining molecular dynamics simulations and a biologically relevant cell-based assay
Xu, W., et al.
Biochem. Pharmaco1 242(Pt.2) (2025) 117300 DOI 10.1016/j.bcp.2025.1173003
‘purchased from AnaSpec (Fremont, CA). The following P6-27 analogues, featuring a lactam bridge between Glu16 and Lys20, and P6-38 analogues, containing a lactam bridge between Glu25 and Lys29‘Serum Stabilities of Short Tryptophan- and Arginine-Rich Antimicrobial Peptide Analogs
Nguyen, L., et al.
Plos one. 5 Issue 9 (2010) DOI 10.1371/journal.pone.0012684
‘All peptides were synthesized using standard 9-fluorenylmethyoxycarbonyl (Fmoc) chemistry and purified by HPLC to >95% purity. They were obtained from Anaspec...Hyphens around certain sequences represent head-to-tail backbone cyclization‘Polymeric conjugates of mono- and bi-cyclic αVβ3 binding peptides for tumor targeting
Mitra, A., et al.
J .Contr. Release. 114 Issue 2 (2006) 175-183 DOI 10.1016/j.conrel.2006.06.014
‘RGD4C (KACDCRGDCFCG, Mw 1273.9) and RGDfK (Mw 604.5) were obtained from AnaSpec...(RGDfK) with high affinity for αVβ3 has a highly stable monocyclic structure with head-to-tail cyclization containing a d-amino acid‘
Specifications
We manufacture custom Lactam cyclized peptides in Research to GMP grades.
- Length: 5-15 amino acids.
- Quantity: 1 mg minimum up to 1kg, delivered as gross weight or net weight.
- Purity:
Research Grade - ≥95%, ≥90%, ≥85%, ≥70% or crude
GMP Grade - ≥95% or ≥98%
Benefits
Lactam cyclization can improve peptide characteristics and pharmacokinetics including:
- Binding affinity to targets
(ie., cell receptors or
protein-protein interactions (PPIs) - Membrane permeability
- Metabolic stability & bioavailability
- Bioactivity
Conformational Effects
Linear peptides can adopt several conformations when interacting with complex biomolecules, not all of which are desired. Head-to-tail lactam cyclization can help lock or constrain the peptide into a preferred 3D structure.
Side-chain-to-side-chain cyclization has been used to stabilize the
α-helical conformation of short peptides (helix-inducing macrocyclic constraints). Making use of the natural amino acids (Lys, Asp, Glu) for stapling, can be preferable over unnatural staple building blocks.
Cyclic RGD peptides and analogues have been lactam cyclized to function as peptidomimetics influencing cellular adhesion and migration in different cellular states.
