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| Product Name | Fmoc-Leu-OH |
|---|---|
| Synonyms | Nα-Fmoc-L-leucine; Fmoc-L-leucine |
| Catalog No. | AS0304 |
| CAS Number | 35661-60-0 |
| Molecular Formula | C21H23NO4 |
| Molecular Weight | 353.41 g/mol |
| Appearance | White powder |
| Melting Point | 148–163°C |
| Specific Rotation | -25° ± 2° (C=1 in DMF) |
| Storage Temperature | Cool, dry place (≤25°C) |
| Side-Chain Protection | None required |
| Primary Application | Fmoc solid-phase peptide synthesis (SPPS) |
Product Overview
Fmoc-Leu-OH (CAS 35661-60-0; catalog AS0304) is N-Fmoc-L-leucine, a protected amino acid for incorporating Leu into synthetic research peptides. It carries an Fmoc-protected alpha-amino group and a free carboxyl group for coupling. Leucine has an isobutyl side chain and requires no side-chain protecting group for conventional Fmoc-SPPS.
Quality Specifications and Ordering
Purity: Alan Scientific supplies Fmoc-Leu-OH at >99% purity.
Catalog pack sizes: 25 g, 100 g, 500 g, and 1 kg.
Quality documentation: See Product Documents below for lot-specific COA request details. Review the analytical methods and results reported for the supplied batch.
Quotation: Email [email protected] with AS0304, the pack size, total quantity, delivery destination, and required date. Confirm availability and dispatch lead time before ordering.
For repeat synthesis campaigns, include the quantity per run and the expected order schedule. Interpret each lot COA according to the analytical methods actually reported.
Leucine versus Isoleucine
Leucine and isoleucine share the same elemental composition and molecular mass, but their side chains have different connectivity. Leucine is not beta-branched: its branching is farther from the backbone than that of isoleucine. This difference matters when specifying a sequence or interpreting steric effects.
A mass value alone cannot establish whether the intended Leu or Ile building block has been selected. Match the complete product identity and structure, rather than using molecular weight as the sole procurement check.
Hydrophobic Sequences and Resin-Bound Accessibility
Applications include Leu-containing research peptides, hydrophobic sequence motifs, and substitution libraries investigating side-chain packing. The behavior of a Leu-rich sequence depends on the complete residue arrangement and not simply on the number of leucines.
When a growing peptide aggregates on the resin, access to reactive sites can decrease and lead to incomplete synthesis. This is a process and sequence issue, not automatic evidence of an impure leucine reagent. Resin loading, support solvation, and synthesis monitoring should be considered together when evaluating difficult hydrophobic targets.
For persistent difficulty in hydrophobic sequences, review resin loading and aggregation in the SPPS practical guide rather than relying only on repeated coupling steps.
Product Documents
A Safety Data Sheet (SDS / MSDS) is available for this product to support laboratory handling, storage and safety assessment.
Certificates of Analysis are batch-specific. Please contact us to request a COA, and we will provide it by email.
Frequently Asked Questions
Can I order Fmoc-Leu-OH for a repeat peptide-synthesis campaign?
Fmoc-Leu-OH is listed in 25 g, 100 g, 500 g, and 1 kg packs. Provide AS0304, expected consumption, and the required delivery schedule when requesting a quotation. Qualify the supplied lot against your acceptance criteria; a repeat order does not automatically reserve the same lot.
Is leucine a beta-branched amino acid?
No. Its isobutyl side chain branches farther from the alpha-carbon than the side chains of valine or isoleucine.
Does a hydrophobic sequence require a different purity grade of Fmoc-Leu-OH?
Not necessarily. First separate reagent-specification requirements from sequence-dependent synthesis problems such as resin-bound aggregation.
Research Use Only
For research use only. Not for human or veterinary use.