4-Borono-D-Phenylalanine: Properties, Uses & FAQs

4-Borono-D-phenylalanine is a boron-containing D-amino acid analogue of phenylalanine that serves as a key research reagent in boron neutron capture therapy (BNCT) studies and related biochemical investigations.

Chemical Name

4-Borono-D-phenylalanine

SKU

B165946

Compound Class

Boronic acid-substituted D-amino acid

Stereochemistry

D-configuration (R-enantiomer of borono-phenylalanine)

Primary Research Application

Boron Neutron Capture Therapy (BNCT) and amino acid transport studies

Key Functional Group

Arylboronic acid (-B(OH)₂) at the para position of the phenyl ring

What Is 4-Borono-D-Phenylalanine?

4-Borono-D-phenylalanine (D-BPA) is the D-stereoisomer of 4-borono-phenylalanine, a synthetic amino acid in which the para position of the phenylalanine phenyl ring bears a boronic acid (-B(OH)₂) functional group. This structural modification imparts unique properties relevant to boron delivery and cellular uptake studies.

The compound belongs to the class of arylboronic acid derivatives and is closely related to the clinically investigated L-enantiomer (L-BPA), which has been extensively studied as a boron delivery agent for Boron Neutron Capture Therapy (BNCT). The D-isomer serves as a critical stereochemical reference compound and research tool, enabling scientists to probe enantioselective transport mechanisms, receptor specificity, and stereoselective biochemical interactions.

As a research reagent supplied by Aladdin Scientific (SKU: B165946), 4-Borono-D-phenylalanine supports a range of in vitro and mechanistic studies in oncology, radiobiology, and amino acid transport research.

Research Applications and Scientific Significance

4-Borono-D-phenylalanine finds its primary utility as a stereochemical control compound in BNCT-related research. Because BNCT relies on selective boron accumulation in tumor cells, understanding how each enantiomer is recognized and transported by amino acid transporters—particularly the large neutral amino acid transporter LAT1 (SLC7A5)—is of fundamental importance.

Key research applications include:

• Stereoselective transport studies: D-BPA is used alongside L-BPA to determine the enantioselectivity of LAT1 and related amino acid transporters, providing mechanistic insight into tumor-selective boron uptake.
• BNCT mechanistic research: As a negative or comparative control, D-BPA helps researchers delineate transport-dependent versus passive accumulation of boronated compounds in cancer cells.
• Biochemical and structural studies: The compound supports crystallography, NMR, and binding assays that investigate how boronic acid-substituted amino acids interact with transport proteins and enzymes.
• Drug design reference: D-BPA provides stereochemical benchmarks for the development of novel boron-containing amino acid prodrugs and BNCT agents.

Its high structural similarity to natural phenylalanine makes it a valuable probe for studying amino acid metabolism and transport with minimal structural perturbation beyond the boronic acid substituent and stereochemical inversion.

Handling, Storage, and Preparation Guidelines

Proper handling and storage of 4-Borono-D-phenylalanine are essential to maintain reagent integrity and experimental reproducibility. The following general guidelines apply; always consult the product-specific Certificate of Analysis (CoA) and Safety Data Sheet (SDS) supplied with SKU B165946 for confirmed specifications.

• Storage: Store the solid compound in a cool, dry, well-ventilated location, away from light and moisture. Refrigerated storage (2–8 °C) is generally recommended for boronic acid-containing amino acids to minimize slow oxidative or hydrolytic degradation; confirm the recommended condition on the CoA.
• Solubility: Borono-phenylalanine derivatives are typically sparingly soluble in water at neutral pH, but solubility increases under mildly basic conditions or in dilute aqueous base. Stock solutions are commonly prepared in 0.1 M NaOH or phosphate-buffered saline adjusted to slightly basic pH, then diluted into the desired buffer. Verify solubility under your specific experimental conditions before use.
• Handling: Use standard laboratory PPE (gloves, lab coat, eye protection). Avoid generating dust when weighing. Boronic acid compounds may exhibit mild irritant properties; consult the SDS for hazard information.
• Stability: As with most boronic acid compounds, solutions should be freshly prepared or stored under inert atmosphere at low temperature to prevent oxidation of the boronic acid moiety.

Contact Aladdin Scientific technical support for application-specific preparation advice.

Distinguishing D-BPA from L-BPA in Experimental Design

A frequent source of confusion in BNCT and amino acid transport research is the distinction between the D- and L-enantiomers of borono-phenylalanine. Understanding their differences is critical for rigorous experimental design.

L-BPA is the pharmacologically active enantiomer investigated in clinical BNCT settings. It is recognized by LAT1 and related transporters that preferentially handle L-amino acids, enabling selective accumulation in rapidly proliferating tumor cells that overexpress these transporters.

D-BPA (SKU: B165946), by contrast, is not expected to be efficiently transported by the same stereospecific amino acid transporters and therefore serves primarily as:

• A negative control to confirm that observed cellular boron uptake of L-BPA is transporter-mediated rather than passive.
• A tool for probing whether any non-selective or D-amino-acid-preferring transport pathways contribute to boron accumulation.
• A stereochemical reference for spectroscopic and analytical method validation.

Researchers should clearly label and segregate stock solutions of D- and L-BPA to avoid inadvertent mix-ups, which could significantly compromise experimental conclusions.

Ordering, Purity, and Quality Assurance

4-Borono-D-phenylalanine is available from Aladdin Scientific under SKU B165946. When ordering or evaluating this reagent, consider the following quality-related points:

• Purity: Research-grade boronic acid amino acids should meet defined purity thresholds (typically ≥95% by HPLC) to ensure experimental reproducibility. Refer to the current CoA available on the Aladdin Scientific product page for the precise purity value of your lot.
• Enantiomeric excess (ee): For stereospecific mechanistic studies, the enantiomeric purity of D-BPA is critical. Request the ee value or chiral HPLC data from the CoA to confirm the stereochemical integrity of the supplied material.
• Lot-specific documentation: Each shipment is accompanied by a CoA detailing identity (NMR, MS or IR confirmation), purity, and appearance. Retain this documentation for GLP or regulatory compliance purposes.
• Quantity and packaging: Contact Aladdin Scientific sales or visit the product page for available pack sizes, pricing, and volume discount information.
• Custom synthesis: For specialized purity grades, isotopically labeled variants (e.g., ¹⁰B-enriched D-BPA), or bulk quantities, contact Aladdin Scientific for custom synthesis options.

For procurement questions, returns, shipping terms, and payment options, please refer to the relevant Aladdin Scientific help center sections or contact customer service directly.

Frequently asked questions

What is the difference between 4-Borono-D-phenylalanine and 4-Borono-L-phenylalanine?

4-Borono-D-phenylalanine and 4-Borono-L-phenylalanine are non-superimposable mirror-image enantiomers that differ in the stereochemical configuration at the alpha-carbon. The L-enantiomer is the biologically active form investigated in BNCT clinical research because it is preferentially recognized and transported into tumor cells by stereospecific amino acid transporters such as LAT1. The D-enantiomer (SKU: B165946) is not efficiently transported by these same L-selective carriers, making it an indispensable negative control in mechanistic transport studies.

How should I prepare a stock solution of 4-Borono-D-phenylalanine for cell-based assays?

Borono-phenylalanine derivatives are generally sparingly soluble in water at physiological pH; solubility can be improved by dissolving the compound in a small volume of 0.1 M NaOH and then diluting into the appropriate assay buffer to the desired working concentration, adjusting pH as needed. Fresh preparation is recommended to prevent oxidation of the boronic acid moiety. Always verify actual solubility under your specific experimental conditions and refer to the CoA for confirmed solubility data for lot B165946.

Why is the D-enantiomer of BPA used as a control in BNCT transport experiments?

The use of D-BPA as a control allows researchers to confirm that cellular boron accumulation observed with L-BPA is mediated by stereospecific amino acid transporters (primarily LAT1) rather than non-specific passive diffusion. Because LAT1 and most physiologically relevant amino acid transporters exhibit strong enantioselectivity for L-amino acids, significantly lower intracellular boron levels with D-BPA compared to L-BPA provide direct evidence of active, transporter-mediated uptake, which is essential for interpreting BNCT selectivity data.

What analytical methods are used to confirm the identity and purity of 4-Borono-D-phenylalanine?

Standard analytical methods for identity confirmation typically include nuclear magnetic resonance spectroscopy (¹H NMR and ¹¹B NMR), mass spectrometry (MS), and infrared spectroscopy (IR). Purity is commonly assessed by high-performance liquid chromatography (HPLC), and enantiomeric purity is verified by chiral HPLC. The specific analytical data for each lot of SKU B165946 are documented in the product Certificate of Analysis (CoA), which should be reviewed upon receipt.

Is 4-Borono-D-phenylalanine suitable for in vivo studies?

4-Borono-D-phenylalanine (SKU: B165946) is supplied as a research-grade reagent intended primarily for in vitro mechanistic and biochemical studies. Any use in in vivo settings requires researchers to independently assess biocompatibility, formulation requirements, regulatory compliance, and institutional animal care protocols. Aladdin Scientific does not supply this compound with claims of suitability for clinical or therapeutic use.

References

1. Mishima Y, et al. Selective thermal neutron capture therapy of cancer guided by an in vivo target-seeking boron compound. Journal of Investigative Dermatology, 1989. [Foundational reference for BPA in BNCT — specific volume/page to be verified]
2. Kanai Y, et al. Expression cloning and characterization of a transporter for large neutral amino acids activated by the heavy chain of 4F2 antigen (CD98). Journal of Biological Chemistry, 1998. [LAT1 transporter enantioselectivity reference — details to be confirmed]
3. Barth RF, et al. Boron neutron capture therapy of cancer: current status and future prospects. Clinical Cancer Research, 2005. [General BNCT review — volume and page numbers to be verified]

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.