The following data was supplied with the peptides by themanufacturer;
- Safety
- Storage
- Container
- Dissolution
- Dissolution approach1
- Dissolution approach2
- Dissolution approach3
- Storage ofSolutions
- Feedback notes
Material Safety Note: THIS PRODUCT IS NOT LICENSED OR APPROVEDFOR ADMINISTRATION TO HUMANS OR ANIMALS
Use due caution in handling and use of this product. A MaterialSafety Data Sheet for this investigational material is notavailable as its chemical, physical and toxicological propertieshave not been fully investigated. Exercise due care. Do not takeinternally. Avoid breathing dust. Wear suitable protective clothingand gloves. If any irritation occurs, obtain immediate medicalattention.
Do not release spilled or wasted material to the environment. Thismaterial should be handled in a restricted manner until its degreeof risk has been adequately assessed.
NIBSC CJD Resource Centre is not aware of any specific hazard dataapplicable to this material nor of any requirements regarding therestricted disposal of the compound. Standard Laboratory Proceduresshould be employed when handling this material. If in doubt contactyour Site Safety personnel for advice.
NIBSC CJD Resource Centre cannot guarantee completeness or accuracyof the information contained herein and further disclaims allliability for its handling or use.
Storage of peptides:
Peptides should be stored in a dry, cool, darkplace. For best preservation, store at 4°C or colder away frombright light. Dry peptides are stable at room temperature for daysto weeks but for long-term storage -20°C is to be preferred.
Contamination with moisture will greatly decrease long termstability of solid peptides. A vial containing a peptide should beallowed to warm to room temperature prior to being opened. Afterremoving the desired quantity, the vial should be re-sealed,preferably under an atmosphere of dry inert gas, and then returnedto cold storage.
Choice of containerAn ideal container for peptide manipulation shouldbe clean, chemically inert, optically clear, strong and availablein an appropriate size. Glass and plastic vials are generallysatisfactory for the purpose, however, care does need to be takenwith plastic vials when organic solvents are to be used.Polypropylene vials are both strong and chemically inert but ifhigh visibility is required glass is a better option. Pleaseappreciate that peptides in solution can and do adsorb to manymaterials. This may occur to varying extents being dependent uponfactors such as constituent amino acids, vial material, and peptideconcentration. At high dilution it is possible to lose largepercentages of peptide due to adsorption to surfaces therebygrossly distorting subsequent results. Use of high qualityspecialist glass and polypropylene vials can lessen thisproblem.
Peptide dissolutionThere is no ideal solvent that will solubilise allpeptides whilst maintaining their integrity and being compatiblewith biological assays. It may prove necessary to use a series ofincreasingly powerful solvents until the peptide dissolves. Forpeptides with a solubility problem the following guidelines mayprove of help.
Approach 1:In general, attempt to dissolve peptides in steriledistilled water or sterile dilute acetic acid (0.1%) solution togive a stock solution at a higher concentration than that requiredfor subsequent use. This solution may later be diluted with anappropriate buffer. If the peptide persists as visible particles,sonication may prove of help as it improves the rate ofdissolution. If, after sonication, the ’solution’ has gelled, has apersistent haziness, or has a scum floating on the surface, thepeptide has probably not dissolved but is simply finelysuspended.
Approach 2:If the peptide remains Insoluble, look at Its aminoacid composition prior to proceeding further. What proportion ofamino acids are hydrophobic (A, C, F, I, L, M, P, V, W, Y) and howmany residues are positively charged (K, R, H, and amino terminus)or negatively charged (D, E, and carboxy terminus)? What is theoverall net charge at neutral pH? If there is a net charge atneutral pH, addition of dilute acetic acid (for basic, positivelycharged peptides) or dilute aqueous ammonia or ammonium bicarbonate(for acidic, negatively charged peptides) with further sonicationshould greatly aid solubility. The final concentration of aceticacid or ammonia/ammonium bicarbonate allowable will be determinedby the use to which the peptide is to be finally put. If thepeptide still refuses to dissolve, these volatile buffer systemsmay be removed by lyophilisation and alternative solvents tried onthe same peptide sample.
Approach 3:If the peptide sequence has little or no net chargeat any pH, or if the number of hydrophobic residues approaches 50%or more, +he chances are +ha+ +he above procedures may proveinadequate. Addition of acetonitrile, ethanol, dimethylformamide(DMF) dimethyl sulphoxide (DMSO), or the use of chaotropic saltssuch as guanidine hydrochloride or urea should aid the dissolutionof most peptides. The choice will depend largely on thecompatibility of such reagents with the subsequent peptideapplication. If it is known that the peptide is slightly soluble inaqueous solution, it is better to first dissolve it completely in asmall amount of neat acetic acid or DMF and then slowly dilute withwater or buffer rather than to add such solvent progressively to asuspension of the peptide in aqueous systems
Storage of peptide solutions:The shelf life of peptide solutions is limitedespecially for peptides containing C, M, N, Q, and W. To prolongthe storage life of peptides in solution, sterile buffers with a pHof around 5-6 should be used. Aliquots should be stored at -20°C orcolder wherever possible. Avoid the use of frost-free freezers,which vary enormously in temperature during the frequent automaticdefrosting cycles. Repeated freeze-thaw cycles are deleterious topeptides.
Feedback Note: 28/08/03
