Solid-phase peptide synthesis: difference between revisions
Diff·revision 11 → 12·16:04, 13 Oct 2024
Difference between revision 11 and revision 12 of Solid-phase peptide synthesis. 11 lines changed; the page grew by 631 bytes.
| Revision 11 — 20:44, 30 Sep 2024 StopperingSteff (talk) rm the shipping recommendation — that is advice, not description 2,718 bytes ±0 | Revision 12 — 16:04, 13 Oct 2024 LedeLeander (talk) correct the transit-time figure — the source gives a median, not a maximum 3,349 bytes +631 | ||
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| 22 | Resin loading — millimoles of site per gram — sets the scale and also affects chain crowding. High loading gives more material per batch but increases the chance of interchain aggregation on the support, which is the main cause of difficult couplings. See [[Peptide aggregation]] for the solution-phase analogue of the same phenomenon.{{r|merrifield1963}} | 22 | Resin loading — millimoles of site per gram — sets the scale and also affects chain crowding. High loading gives more material per batch but increases the chance of interchain aggregation on the support, which is the main cause of difficult couplings. See [[Peptide aggregation]] for the solution-phase analogue of the same phenomenon.{{r|merrifield1963}} |
| 23 | 23 | ||
| + | 24 | == Difficult sequences == | |
| + | 25 | Some sequences couple readily and some do not. Stretches rich in β-branched or hydrophobic residues promote secondary structure on the resin, burying the reactive N-terminus and depressing coupling yield locally.{{r|behrendt2016}} | |
| + | 26 | ||
| + | 27 | | Countermeasure | Mechanism | | |
| + | 28 | |---|---| | |
| + | 29 | | Elevated temperature or microwave heating | Disrupts on-resin structure | | |
| + | 30 | | Chaotropic or polar aprotic solvents | Reduces interchain association | | |
| + | 31 | | Double coupling | Second exposure to activated residue | | |
| + | 32 | | Pseudoproline dipeptides | Introduces a kink that prevents β-sheet | | |
| + | 33 | | Lower resin loading | Reduces chain crowding | | |
| + | 34 | ||
| 24 | == References == | 35 | == References == |
| 25 | {{reflist}} | 36 | {{reflist}} |