Fmoc chemistry: difference between revisions
Diff·revision 10 → 11·19:54, 27 Oct 2024
Difference between revision 10 and revision 11 of Fmoc chemistry. 5 lines changed; the page grew by 665 bytes.
| Revision 10 — 21:57, 8 Oct 2024 GlossaryGleb (talk) correct the humidity figure — relative humidity needs its temperature 2,683 bytes ±0 | Revision 11 — 19:54, 27 Oct 2024 SelectTrialSam (talk) state the difference between a validated shipper and an insulated box 3,348 bytes +665 | ||
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| 21 | Side-chain protection uses acid-labile groups: tert-butyl for hydroxyl and carboxyl side chains, trityl for cysteine and asparagine, and sulfonyl-type groups for arginine. All are removed in the final acidic cleavage. See [[Resin cleavage]].{{r|usp1503}} | 21 | Side-chain protection uses acid-labile groups: tert-butyl for hydroxyl and carboxyl side chains, trityl for cysteine and asparagine, and sulfonyl-type groups for arginine. All are removed in the final acidic cleavage. See [[Resin cleavage]].{{r|usp1503}} |
| 22 | 22 | ||
| + | 23 | == Characteristic side reactions == | |
| + | 24 | Repeated base exposure has costs. Aspartimide formation is the most consequential: an aspartate residue can cyclise with the following backbone nitrogen under basic conditions, and the resulting succinimide reopens to give both the desired product and an isomer. Aspartate followed by glycine is the worst context — the same sequence dependence seen in [[Deamidation|deamidation]].{{r|behrendt2016}} | |
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| + | 26 | Racemisation occurs mainly at the activation step rather than at deprotection, and is worst at histidine and cysteine. It is invisible to [[Mass spectrometry|mass spectrometry]], since epimers are isobaric.{{r|behrendt2016}} | |
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| 23 | == References == | 28 | == References == |
| 24 | {{reflist}} | 29 | {{reflist}} |