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| Product Name | Fmoc-Arg(Pbf)-OH |
|---|---|
| Synonyms | Nα-Fmoc-Nω-Pbf-L-arginine; Nα-Fmoc-Nω-(2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl)-L-arginine |
| Catalog No. | AS2484 |
| CAS Number | 154445-77-9 |
| Molecular Formula | C34H40N4O7S |
| Molecular Weight | 648.77 g/mol |
| SMILES | Cc1c(C)c(c(C)c2CC(C)(C)Oc12)S(=O)(=O)NC(=N)NCCCC@HC(O)=O |
| Storage Temperature | Cool, dry place (≤25°C) |
| Appearance | White to off-white powder |
| Specific Rotation | -4.5° ± 1.5° (C=4 in DMF) |
| Functional Groups | Fmoc-protected α-amino group; Pbf-protected guanidino side chain; carboxylic acid |
| Primary Application | Fmoc solid-phase peptide synthesis (SPPS) |
Product Overview
Fmoc-Arg(Pbf)-OH is a protected L-arginine derivative widely used as a building block for introducing arginine residues during Fmoc-based solid-phase peptide synthesis (SPPS).
The α-amino group is protected by Fmoc, while the strongly basic guanidino side chain of arginine is protected by the Pbf (2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl) group. This protecting-group combination helps minimize undesired side-chain reactions during iterative peptide coupling and deprotection cycles.
Pbf is acid-labile and can be removed during final TFA-based peptide cleavage and global deprotection, making Fmoc-Arg(Pbf)-OH one of the most commonly used protected arginine building blocks in modern Fmoc-SPPS.
Applications in Peptide Synthesis
| Application | Role of Fmoc-Arg(Pbf)-OH |
|---|---|
| Fmoc Solid-Phase Peptide Synthesis | Standard building block for incorporation of L-arginine into synthetic peptide sequences |
| Arginine-Rich Peptide Synthesis | Supports preparation of peptides containing multiple positively charged arginine residues |
| Cell-Penetrating Peptides | Useful for synthesis of arginine-rich CPP sequences involved in cellular uptake studies |
| Nuclear Localization Signal Peptides | Incorporation of arginine residues into basic NLS sequences used in intracellular targeting research |
| Antimicrobial Peptide Research | Building block for cationic peptides in which arginine contributes to membrane interactions |
| Peptide Library Synthesis | Used in parallel synthesis of sequence-diverse arginine-containing peptide libraries |
| Structure–Activity Relationship Studies | Supports preparation of peptide analogs for evaluating the contribution of arginine to binding and biological activity |
Fmoc-Arg(Pbf)-OH in Fmoc-SPPS
During Fmoc-SPPS, Fmoc-Arg(Pbf)-OH is activated and coupled to the growing resin-bound peptide chain while the α-amino group remains protected by Fmoc.
Following coupling, standard Fmoc deprotection exposes the α-amino group for the next elongation cycle, while the Pbf group remains attached to the arginine guanidino side chain throughout peptide assembly.
At the end of synthesis, acidic cleavage conditions commonly based on TFA remove the Pbf side-chain protecting group together with other acid-labile protecting groups, producing the free arginine-containing peptide.
Because arginine contains a highly basic and reactive guanidino group, appropriate side-chain protection is particularly important for maintaining synthetic control during peptide assembly.
Role of Pbf Protection in Arginine Peptide Synthesis
The Pbf protecting group is widely used for guanidino protection in Fmoc peptide chemistry because it provides good stability during routine Fmoc deprotection and peptide coupling while remaining removable under acidic final-cleavage conditions.
Compared with older arginine protecting groups, Pbf is designed to facilitate efficient final deprotection and is commonly selected for the synthesis of arginine-containing and arginine-rich peptides.
This is particularly relevant for peptides such as cell-penetrating peptides (CPPs), nuclear localization signals (NLS), antimicrobial peptides, and other cationic peptide sequences, where several arginine residues may be incorporated into a single peptide.
For difficult or highly arginine-rich sequences, coupling efficiency, aggregation, reagent equivalents, and cleavage conditions should be optimized according to the individual peptide sequence.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage, and safety assessment.
📎 MSDS_Fmoc-Arg(Pbf)-OH_AS2484.pdf
Related Technical Resources
Learn more about protected amino acids and peptide chain assembly in Solid-Phase Peptide Synthesis (SPPS): A Practical Guide.
Explore additional Standard Fmoc-Amino Acids for peptide synthesis applications.
For complete peptide projects, Alan Scientific also provides Custom Peptide Synthesis including synthesis, purification, modification, and analytical quality control.
Why Source Peptide Building Blocks from Alan Scientific?
Alan Scientific supplies protected amino acids and peptide building blocks for research and peptide synthesis applications, with competitive pricing, flexible ordering options, and peptide synthesis technical support.
Researchers can source individual Fmoc amino acids or combine building-block procurement with custom peptide synthesis services according to project needs.