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Z-Phe-Trp-OH is an N-Cbz-protected Phe-Trp dipeptide with a free C-terminal tryptophan carboxyl group. It provides a preassembled aromatic dipeptide motif for fragment coupling and solution-phase peptide synthesis.
Phe-Trp is more than a two-residue spacer. Two bulky aromatic side chains are presented in adjacent positions, which can influence hydrophobicity, chromatographic retention and local stacking interactions in the final peptide.
Product Information
| Product Name | Z-Phe-Trp-OH |
| Catalog No. | AS4154 |
| CAS No. | 16856-28-3 |
| Molecular Formula | C28H27N3O5 |
| Molecular Weight | 485.54 g/mol |
| Building Block Type | Cbz-protected aromatic dipeptide fragment |
| Primary Applications | Protected-fragment synthesis; solution-phase coupling; Phe-Trp motif assembly; aromatic peptide intermediates |
Why Use a Preformed Phe-Trp Fragment
A preassembled Phe-Trp unit removes one peptide-bond-forming step from the downstream route and provides a separately characterized aromatic fragment. This can be useful when the same motif is repeated across an analog series or when late-stage coupling is already synthetically demanding.
Aromatic Content Changes Peptide Behavior
Phenylalanine and tryptophan can increase hydrophobicity and RP-HPLC retention, especially when they occur next to one another. We consider this relevant not only to synthesis but also to purification: an aromatic-rich segment that couples cleanly can still complicate post-cleavage solubility and recovery.
Cbz Protection and Reductive Deprotection
The N-terminal Phe is protected as Cbz, while the Trp carboxyl remains available for extension. Cbz is commonly removed reductively, so the timing of deprotection should be planned around other reducible groups. For comparison, Z-Phe-Gly-OH provides a much less hydrophobic Cbz-protected Phe-containing fragment.
Analytical Identity of an Aromatic Dipeptide
Confirm CAS 16856-28-3, formula C28H27N3O5 and MW 485.54 g/mol. Because aromatic fragments can show strong UV response, HPLC area can look deceptively favorable if compared with impurities of different chromophore content; LC-MS remains an important complementary identity check.
Procurement and QC Considerations
For sequence-level work, consider whether the Phe-Trp motif will create hydrophobicity or purification constraints in the complete peptide. Those questions can be reviewed during custom peptide synthesis planning.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
Certificates of Analysis (COAs) are batch-specific. Please contact us to request the COA for your product, and we will provide it by email.
Frequently Asked Questions
What is Z-Phe-Trp-OH used for?
It is used as a protected Phe-Trp dipeptide fragment in peptide and intermediate synthesis.
Is the C-terminal Trp carboxyl free?
Yes, it remains available for activation and further coupling.
Does Cbz removal affect tryptophan?
Route compatibility should be evaluated because reductive conditions must be selected for the full molecule.
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