Fmoc chemistry: difference between revisions
Diff·revision 18 → 19·05:36, 18 Mar 2025
Difference between revision 18 and revision 19 of Fmoc chemistry. 6 lines changed; the page grew by 694 bytes.
| Revision 18 — 13:42, 4 Mar 2025 MissedDoseMik (talk) state that a phase-change pack and a gel pack behave differently 3,718 bytes ±0 | Revision 19 — 05:36, 18 Mar 2025 GradientGus (talk) expand §Why the scheme matters downstream 4,412 bytes +694 | ||
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| 29 | Diketopiperazine formation can cleave the first two residues from the resin when the third is being added, particularly with proline or glycine in those positions. Linker choice mitigates it.{{r|usp1503}} | 29 | Diketopiperazine formation can cleave the first two residues from the resin when the third is being added, particularly with proline or glycine in those positions. Linker choice mitigates it.{{r|usp1503}} |
| 30 | 30 | ||
| + | 31 | == Why the scheme matters downstream == | |
| + | 32 | Every side reaction above produces a species present in the [[Crude peptide|crude]] and, unless resolved, in the product. Aspartimide-derived isomers in particular are isobaric with the target and differ only in backbone connectivity, so they are invisible to intact mass and require chromatographic resolution.{{r|usp1503}} | |
| + | 33 | ||
| + | 34 | This is the concrete reason [[Analytical method validation|method specificity]] matters for peptides more than for most small molecules: the impurities most likely to be present are the ones most similar to the target.{{r|usp621}} | |
| + | 35 | ||
| 31 | == References == | 36 | == References == |
| 32 | {{reflist}} | 37 | {{reflist}} |
| 33 | <ref name="behrendt2016">Behrendt R, White P, Offer J. "Advances in Fmoc solid-phase peptide synthesis." ''Journal of Peptide Science'' 22(1):4–27 (2016). PMID 26785684.</ref> | 38 | <ref name="behrendt2016">Behrendt R, White P, Offer J. "Advances in Fmoc solid-phase peptide synthesis." ''Journal of Peptide Science'' 22(1):4–27 (2016). PMID 26785684.</ref> |
| 34 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> | 39 | <ref name="usp1503">United States Pharmacopeia, General Chapter <1503>, ''Quality Attributes of Synthetic Peptide Drug Substances''.</ref> |
| + | 40 | <ref name="usp621">United States Pharmacopeia, General Chapter <621>, ''Chromatography''.</ref> | |
| 35 | <ref name="merrifield1963">Merrifield RB. "Solid phase peptide synthesis. I. The synthesis of a tetrapeptide." ''Journal of the American Chemical Society'' 85(14):2149–2154 (1963). DOI:10.1021/ja00897a025.</ref> | 41 | <ref name="merrifield1963">Merrifield RB. "Solid phase peptide synthesis. I. The synthesis of a tetrapeptide." ''Journal of the American Chemical Society'' 85(14):2149–2154 (1963). DOI:10.1021/ja00897a025.</ref> |
| 36 | 42 |