I am trying to do a kinetics characterisation of AB-40 and AB-42 (they are recombinant peptides produced in the laboratory) but it seems that the samples ar alredy aggregated when I try to do the kinetics mesurement. This peptids, after the purification procedure, are storaged at -20°C and in a solution with a pH of at least 8. I was trying to disaggregate using sonication but it doen't work so well, i was wondering if there is another method I can use for the sample preparation.
Dear Maria Cecilia Morcillo Muñoz ,
You refer to amyloid beta peptides that are highly hydrophobic peptides. I came across the following paper that might be useful to you:
Broersen, K., Jonckheere, W., Rozenski, J., Vandersteen, A., Pauwels, K., Pastore, A., ... & Schymkowitz, J. (2011). A standardized and biocompatible preparation of aggregate-free amyloid beta peptide for biophysical and biological studies of Alzheimer's disease. Protein Engineering, Design & Selection, 24(9), 743-750.
Article A standardized and biocompatible preparation of aggregate-fr...
If you have a powder form of the peptide you could ‘simply’ use DMSO or TFE (after TFA treatment) see for example:
Article Tryptophan fluorescence study on the interaction of the sign...
where a highly hydrophobic signal peptide was used.
Hope this helps you a bit further.
Best regards.
Dear Maria Cecilia Morcillo Muñoz ,
You refer to amyloid beta peptides that are highly hydrophobic peptides. I came across the following paper that might be useful to you:
Broersen, K., Jonckheere, W., Rozenski, J., Vandersteen, A., Pauwels, K., Pastore, A., ... & Schymkowitz, J. (2011). A standardized and biocompatible preparation of aggregate-free amyloid beta peptide for biophysical and biological studies of Alzheimer's disease. Protein Engineering, Design & Selection, 24(9), 743-750.
Article A standardized and biocompatible preparation of aggregate-fr...
If you have a powder form of the peptide you could ‘simply’ use DMSO or TFE (after TFA treatment) see for example:
Article Tryptophan fluorescence study on the interaction of the sign...
where a highly hydrophobic signal peptide was used.
Hope this helps you a bit further.
Best regards.
You can add some mild non-ionic detergents to keep them from aggregating or use more harsh chemicals such as urea, guanidinium-HCl, or SDS to prevent disaggregate. It is easier to prevent aggregation than to disaggregate, so keeping these in small amounts of mild detergents such as tween, Triton X-100, etc. may do the job.
Do they have free cysteines, free thiol-groups, which are not involved in disulfide bridges?
Depending on your buffer and the storage conditions, they may have oxidized (availability of oxygen, etc.) and formed SS-bridges. Try adding a bit of a mild reducing agent, like mercaptoethanol or reduced glutathione.
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