Alloc-D-Val-Ala-OH is an N-terminal allyloxycarbonyl (Alloc)-protected dipeptide containing D-valine followed by L-alanine. The D-Val configuration distinguishes this building block from the conventional Alloc-L-Val-L-Ala-OH motif and makes it useful when researchers intentionally want to study how stereochemistry changes peptide-linker conformation, enzymatic recognition or proteolytic stability.

The Alan Scientific SKU is specified as Alloc-D-Val-Ala-OH with molecular formula C₁₂H₂₀N₂O₅ and molecular weight 272.30 g/mol. These elemental data are shared by the corresponding L-Val stereoisomer, so stereochemical identity must be controlled by the product designation, structure and lot-specific analytical documentation rather than by formula or molecular weight alone.

Product Information

Why the D-Val Configuration Matters

Changing an L-amino acid to its D-enantiomer preserves elemental composition and nominal molecular weight but changes the three-dimensional orientation of the peptide backbone and side chain. In a short protease-recognition motif, that stereochemical change can alter enzyme recognition, cleavage rate, linker stability and downstream payload-release behavior.

Alloc-D-Val-Ala-OH is therefore best positioned as a stereochemical analog and research building block, not as a direct substitute for the standard L-Val-Ala linker without experimental validation.

Applications in Cleavable-Linker and Conjugate Research

The D-Val-L-Ala motif can be incorporated into experimental peptide-linker architectures to compare stereochemical effects against the corresponding L-Val-L-Ala sequence. Relevant workflows include antibody-drug conjugate (ADC), peptide-drug conjugate (PDC), protease-responsive linker and targeted-delivery research.

Potential studies include linker design, protease-cleavage profiling, plasma or lysosomal stability testing, conjugate SAR and control experiments designed to determine whether D-Val substitution increases resistance to a selected protease or changes cleavage selectivity.

Alloc Protection and Synthetic Planning

The Alloc group provides an orthogonal N-terminal protecting strategy. It can be retained while other synthetic operations are performed and then removed selectively under suitable palladium-mediated conditions when the downstream route requires exposure of the D-Val amino group.

Because palladium-mediated Alloc deprotection can be sensitive to substrate composition, scavenger choice and downstream metal-removal requirements should be considered when the building block is used in complex linker or peptide-conjugate synthesis.

Alloc-D-Val-Ala-OH vs Alloc-Val-Ala-OH

Alloc-D-Val-Ala-OH and Alloc-Val-Ala-OH have the same elemental formula and molecular weight but are not the same stereochemical material. AS4043 contains D-Val, whereas the conventional Alloc-Val-Ala-OH product corresponds to the L-Val-containing dipeptide.

This distinction is especially important in protease-sensitive linker research because enzymatic cleavage depends on three-dimensional substrate recognition. The two materials should not be interchanged based only on MW or formula.

Downstream Assay Relevance

The protected dipeptide itself is an upstream synthetic intermediate. After incorporation into a completed linker or conjugate, the resulting construct may be evaluated in purified-protease cleavage assays, plasma- or lysosomal-stability studies, payload-release assays, cell-based activity studies and in vivo conjugate experiments where appropriate.

Any claim of increased stability or altered protease selectivity should be established experimentally for the completed linker architecture rather than inferred from the isolated D-Val building block alone.

Identity and Procurement Considerations

For this SKU, stereochemical identity is a critical procurement specification. Molecular formula and molecular weight cannot distinguish D-Val from L-Val. Researchers should confirm the D-Val-L-Ala structure using the product designation and lot-specific COA or other stereochemical analytical documentation.

The CAS number currently associated with the standard L-Val-L-Ala analog should not be used as definitive identification for the D-Val stereoisomer unless the upstream manufacturer specifically supports that assignment. A lot-specific structure and COA are therefore more important than CAS alone for this product.

Product Documents

A Material Safety Data Sheet (MSDS) is available for this product to support laboratory handling, storage and safety assessment.

📎 MSDS_Alloc-D-Val-Ala-OH_AS4043.pdf

Frequently Asked Questions

Is Alloc-D-Val-Ala-OH the same as Alloc-Val-Ala-OH?

No. AS4043 contains D-valine, while the conventional Alloc-Val-Ala-OH motif contains L-valine. The stereoisomers have the same formula and molecular weight but different three-dimensional structures.

Why use D-Val in a Val-Ala linker analog?

D-Val substitution can be used to investigate how stereochemistry influences protease recognition, linker cleavage and stability. The actual effect must be determined experimentally for the completed linker or conjugate.

Can this building block be used in ADC or PDC research?

Yes. It can be used as a stereochemical linker intermediate in experimental ADC, PDC and other protease-responsive conjugate designs, particularly for cleavage-SAR and stability-control studies.

Why is the CAS field not assigned here?

A reliable public CAS assignment for the exact D-Val stereoisomer was not confirmed. The commonly encountered CAS 330970-70-2 corresponds to the L-Val-L-Ala analog, so using that number for AS4043 would create a stereochemical identity mismatch.

Related Technical Resources

Browse Specialty Peptide Building Blocks or discuss custom linker and peptide-conjugate synthesis through our Chemical Peptide Synthesis service.

Research Use Only.