Fmoc-Lys (biotin-PEG4)-OH

Name: Fmoc-Lys (biotin-PEG4)-OH
Brand: BOC Sciences
Rating: 5 (1 reviews)

CAS No.: 1334172-64-3

Cat No.: BP-500943 4.5

Fmoc-Lys (biotin-PEG4)-OH is a protected lysine derivative bearing an Fmoc α-amino group and a side-chain biotin moiety connected through a four-unit polyethylene glycol (PEG) linker. Structurally, it provides a lysine-based attachment handle for solid-phase or solution-phase assembly while the PEG spacer confers aqueous solubility and spatial separation between the biotin tag and the PROTAC scaffold. In targeted protein degradation designs, such lysine–PEG–biotin building blocks are commonly used to introduce a biotin “handle” that can enable affinity capture, immobilization, or detection of PROTAC conjugates via streptavidin-based workflows, without directly replacing the core E3 ligase–recruiting or target-binding pharmacophores. The PEG tether helps preserve functional accessibility of the biotin group and can reduce steric interference during conjugation and assay readouts. This reagent is valuable for researchers developing degraders that require robust pull-down, localization, or quantitative monitoring of molecular constructs.

Structure of 1334172-64-3

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Category

PROTAC Linker

Molecular Formula

C₄₂H₅₉N₅O₁₁S

Molecular Weight

842.01

* For research and manufacturing use only. Not for human or clinical use.

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Please store the product under the recommended conditions in the Certificate of Analysis.

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IUPACName

(2S)-6-[3-[2-[2-[2-[2-[5-[(3aS,4S,6aR)-2-oxo-1,3,3a,4,6,6a-hexahydrothieno[3,4-d]imidazol-4-yl]pentanoylamino]ethoxy]ethoxy]ethoxy]ethoxy]propanoylamino]-2-(9H-fluoren-9-ylmethoxycarbonylamino)hexanoic acid

InChI Key

PNYHBAKBBQCIDX-FWIWLVIWSA-N

InChI

InChI=1S/C42H59N5O11S/c48-37(15-6-5-14-36-39-35(28-59-36)45-41(52)47-39)44-18-20-55-22-24-57-26-25-56-23-21-54-19-16-38(49)43-17-8-7-13-34(40(50)51)46-42(53)58-27-33-31-11-3-1-9-29(31)30-10-2-4-12-32(30)33/h1-4,9-12,33-36,39H,5-8,13-28H2,(H,43,49)(H,44,48)(H,46,53)(H,50,51)(H2,45,47,52)/t34-,35-,36-,39-/m0/s1

SMILES

C1C2C(C(S1)CCCCC(=O)NCCOCCOCCOCCOCCC(=O)NCCCCC(C(=O)O)NC(=O)OCC3C4=CC=CC=C4C5=CC=CC=C35)NC(=O)N2

1. The use of Fmoc-Lys(Pac)-OH and penicillin G acylase in the preparation of novel semisynthetic insulin analogs

Lenka Záková, Daniel Zyka, Jan Jezek, Ivona Hanclová, Miloslav Sanda, Andrzej M Brzozowski, Jirí Jirácek J Pept Sci. 2007 May;13(5):334-41.doi: 10.1002/psc.847.

In this paper, we present the detailed synthetic protocol and characterization of Fmoc-Lys(Pac)-OH, its use for the preparation of octapeptides H-Gly-Phe-Tyr-N-MePhe-Thr-Lys(Pac)-Pro-Thr-OH and H-Gly-Phe-Phe-His-Thr-Pro-Lys(Pac)-Thr-OH by solid-phase synthesis, trypsin-catalyzed condensation of these octapeptides with desoctapeptide(B23-B30)-insulin, and penicillin G acylase catalyzed cleavage of phenylacetyl (Pac) group from Nepsilon-amino group of lysine to give novel insulin analogs [TyrB25, N-MePheB26,LysB28,ProB29]-insulin and [HisB26]-insulin. These new analogs display 4 and 78% binding affinity respectively to insulin receptor in rat adipose membranes.

2. Preparation of the very acid-sensitive Fmoc-Lys(Mtt)-OH. Application in the synthesis of side-chain to side-chain cyclic peptides and oligolysine cores suitable for the solid-phase assembly of MAPs and TASPs

A Aletras, K Barlos, D Gatos, S Koutsogianni, P Mamos Int J Pept Protein Res. 1995 May;45(5):488-96.doi: 10.1111/j.1399-3011.1995.tb01065.x.

N alpha-9-Fluorenylmethoxycarbonyl-N epsilon-4=methyltrityl-lysine, [Fmoc-Lys(Mtt)-OH], was prepared in two steps from lysine, in 42% overall yield. The N epsilon-Mtt function can be quantitatively removed upon treatment with 1% TFA in dichloromethane or with a 1:2:7 mixture of acetic acid/trifluoroethanol/dichloromethane for 30 min and 1 h at room temperature, respectively. Under these conditions, groups of the tert-butyl type and peptide ester bonds to TFA-labile resins, such as the 2-chlorodiphenylmethyl- and the Wang-resin, remained intact. The utility of the new derivative in peptide synthesis has been exemplified with the synthesis of a cyclic cholecystokinin analog. As an example of further application, five types of lysine cores suitable for the solid-phase synthesis of one, two or three epitopes containing antigenic peptides or template-assembled synthetic proteins have been synthesized on Merrifield, Wang and 2-chlorodiphenylmethyl resin.

3. Enhancing the antibacterial effect of chitosan to combat orthopaedic implant-associated infections

Dien Puji Rahayu, Arianna De Mori, Rahmi Yusuf, Roger Draheim, Aikaterini Lalatsa, Marta Roldo Carbohydr Polym. 2022 Aug 1;289:119385.doi: 10.1016/j.carbpol.2022.119385.Epub 2022 Mar 28.

The development of antibacterial resistance imposes the development of novel materials to relieve the burden of infection. Chitosan, a material of natural and sustainable origin, possesses ideal characteristics to translate into a novel biomaterial with antibacterial properties, as it already has these properties and it allows easy and scalable chemical modification to enhance its activity. The aim of the present work was that of producing low molecular weight chitosans that have higher solubility and can remain protonated at physiological pH, thus enhancing the antimicrobial action. This was achieved by reacting acid hydrolysed low molecular weight chitosan with 2-bromoethyleneamine hydrobromide or Fmoc-Lys(Fmoc)-OH to elicit N-(2-ethylamino)-chitosan and N-2(2,6-diaminohexanamide)-chitosan polymers. The latter derivative, CS3H Lys, that was synthesised for the first time, showed superior efficacy against Staphylococcus aureus, supporting further studies for its inclusion in implant coating materials to tackle the burden of orthopaedic implant-associated infections.

Fmoc-Lys (biotin-PEG4)-OH is a multifunctional PROTAC linker building block combining an Fmoc-protected lysine scaffold with a biotin handle and a polyethylene glycol spacer. Its orthogonal functional groups support modular assembly of targeted protein degraders, enabling convenient conjugation to ligands and efficient tuning of linker length and hydrophilicity for improved ternary-complex formation. The detailed structure and reactivity considerations are provided below.

Structure: The molecule contains an Fmoc-protected amino acid framework with a lysine side chain, a biotin moiety, and a PEG-based spacer. It features amide and carbamate linkages, aromatic fluorene-derived protecting-group functionality, and multiple heteroatoms that increase polarity and water compatibility.

Reactivity: The Fmoc group can be removed under standard base-mediated deprotection conditions to reveal a reactive amine for subsequent coupling. PROTAC assembly commonly proceeds via amide-bond formation between the liberated amine and activated carboxylic acid derivatives (for example, NHS- or HATU-type activations) using polar aprotic solvents. The PEG spacer generally remains stable under these coupling and deprotection steps, supporting reproducible synthesis of conjugates.

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* Our calculator is based on the following equation:
Concentration (start) x Volume (start) = Concentration (final) x Volume (final)
It is commonly abbreviated as: C₁V₁ = C₂V₂