L-5-Fluorotryptophan (CAS 16626-02-1) is a fluorinated analogue of L-tryptophan with fluorine at the 5-position of the indole ring. It is used as a peptide synthesis building block, as a precursor to N-protected derivatives, and as a 19F NMR probe in proteins.

L-5-Fluorotryptophan replaces the hydrogen at position 5 of the tryptophan indole ring with fluorine, a small substituent that changes the ring's electronic properties with little steric change. The L-form (CAS 16626-02-1) is distinct from the racemic 5-fluoro-DL-tryptophan (CAS 154-08-5). Medicinal chemists use halogenated tryptophans in cyclic peptide design, and the fluorine atom also serves as an NMR reporter. Hzymes lists L-5-fluorotryptophan in its Enlicitide (MK-0616) building-block series; the free amino acid needs N-protection before solid-phase synthesis.

Product Overview

L-5-Fluorotryptophan, (2S)-2-amino-3-(5-fluoro-1H-indol-3-yl) propanoic acid, is a non-proteinogenic amino acid. Exogenous 5-fluorotryptophan can be incorporated into proteins during normal synthesis, and because 19F is a useful NMR reporter group, it is used to study enzyme mechanisms and protein environments by NMR.

For peptide synthesis, the amino group is usually protected first (for example as an Fmoc or Boc derivative). Contact Hzymes about protected forms and custom requirements.

Key Features

High-Purity Non-Canonical Amino Acid

Hzymes 5-Fluoro-L-tryptophan is manufactured with controlled chemical and optical purity to support reliable and reproducible research.

• HPLC purity ≥99%

• Single impurity ≤0.5%

• Optical purity ee ≥99.9%

• Batch-specific COA available

For researchers seeking a reliable non-canonical amino acid supplier, Hzymes provides 5-Fluoro-L-tryptophan for protein engineering, peptide synthesis, NMR studies, and biocatalysis.

High Optical Purity

The enzymatic synthesis route provides high stereochemical selectivity without conventional chiral resolution.

With ee ≥99.9%, the product is suitable for applications where stereochemical purity is important, including unnatural amino acid incorporation and peptide synthesis.

Enzymatic and Aqueous Synthesis

5-Fluoro-L-tryptophan is produced through an enzyme-catalyzed synthesis route using tryptophan synthase.

The biocatalytic synthesis of fluorotryptophan is performed under aqueous conditions and provides high stereochemical selectivity, supporting the preparation of high-purity fluorinated amino acid building blocks.

Consistent Batch Quality

Key quality attributes are controlled to support consistent product performance across batches.

• Controlled chemical purity

• High optical purity

• Controlled impurity profile

• Water content ≤1%

• Batch-specific Certificate of Analysis

Applications

19F NMR Protein Labeling

5-Fluoro-L-tryptophan can be incorporated into recombinant proteins as an analogue of natural tryptophan.

The fluorine atom provides a sensitive NMR signal with minimal biological background, allowing 5-Fluoro-L-tryptophan to function as a fluorotryptophan NMR probe for studying protein structure and dynamics.

Potential applications include:

• 19F NMR protein labeling

• Protein conformational analysis

• Protein dynamics studies

• Ligand-binding studies

• Enzyme mechanism research

• Molecular interaction studies

Unnatural Amino Acid Incorporation

As a non-canonical amino acid, 5-Fluoro-L-tryptophan can be used in research involving unnatural amino acid incorporation and protein engineering.

Its fluorinated indole structure provides an additional chemical and spectroscopic handle for investigating:

• Protein structure

• Protein dynamics

• Enzyme activity

• Molecular recognition

• Protein–ligand interactions

5-Fluorotryptophan Peptide Synthesis

5-Fluoro-L-tryptophan can be incorporated into peptides to investigate how fluorination affects peptide structure, stability, and biological activity.

Applications include:

• 5-fluorotryptophan peptide synthesis

• Fluorinated peptide design

• Structure–activity relationship studies

• Fluorinated antimicrobial peptides

• Cyclic and macrocyclic peptide research

• Peptide lead optimization

Protected derivatives such as Fmoc-5-Fluoro-L-tryptophan and Boc-5-Fluoro-L-tryptophan can serve as building blocks for solid-phase peptide synthesis, depending on the synthesis strategy.

Metabolic Research

5-Fluoro-L-tryptophan can be used as a fluorinated tryptophan analog in research investigating tryptophan metabolism and enzyme activity.

Potential applications include:

• Tryptophan metabolic pathway studies

• Metabolic flux research

• Enzyme substrate studies

• IDO-related research

• Fluorinated amino acid metabolism

• 5-fluorotryptophan metabolic stability studies

Enzyme Mechanism and Biocatalysis

5-Fluoro-L-tryptophan can serve as a substrate analogue in research involving tryptophan synthase and related enzymes.

It can support studies of:

• Substrate recognition

• Enzyme specificity

• Catalytic mechanisms

• Enzyme engineering

• Tryptophan synthase variants

• Biocatalytic synthesis of fluorotryptophan

Performance Data

Quality Assessment Conforms to product quality specifications

LC-MS Consistent with the expected molecular mass

¹H NMR Consistent with the expected chemical structure

Enantiomeric Purity (ee) 100%

FAQ

What is L-5-fluorotryptophan?

L-5-Fluorotryptophan is a fluorinated analogue of L-tryptophan with a fluorine atom at the 5-position of the indole ring. It is a non-proteinogenic amino acid used in peptide synthesis and NMR studies.

What is the CAS number, and how does it differ from 5-fluoro-DL-tryptophan?

The L-form has CAS 16626-02-1. 5-Fluoro-DL-tryptophan (CAS 154-08-5) is the racemic mixture, so check the stereochemistry before ordering.

Can it be used directly in solid-phase peptide synthesis?

The free amino acid normally needs N-protection first, for example as an Fmoc or Boc derivative. Contact Hzymes about protected forms.

Why use a fluorinated tryptophan?

Fluorine is small, so it alters the electronic character of the indole ring with little steric change, and 19F is NMR-active, so the residue can act as a reporter in NMR experiments.

What documentation is available?

Request the COA and related analytical data with your quote.