The following data was supplied with the peptides by the
manufacturer;
Material Safety Note: THIS PRODUCT IS NOT LICENSED OR APPROVED
FOR ADMINISTRATION TO HUMANS OR ANIMALS
Use due caution in handling and use of this product. A Material
Safety Data Sheet for this investigational material is not
available as its chemical, physical and toxicological properties
have not been fully investigated. Exercise due care. Do not take
internally. Avoid breathing dust. Wear suitable protective clothing
and gloves. If any irritation occurs, obtain immediate medical
attention.
Do not release spilled or wasted material to the environment. This
material should be handled in a restricted manner until its degree
of risk has been adequately assessed.
NIBSC CJD Resource Centre is not aware of any specific hazard data
applicable to this material nor of any requirements regarding the
restricted disposal of the compound. Standard Laboratory Procedures
should be employed when handling this material. If in doubt contact
your Site Safety personnel for advice.
NIBSC CJD Resource Centre cannot guarantee completeness or accuracy
of the information contained herein and further disclaims all
liability for its handling or use.
Storage of peptides:
Peptides should be stored in a dry, cool, dark
place. For best preservation, store at 4°C or colder away from
bright light. Dry peptides are stable at room temperature for days
to weeks but for long-term storage -20°C is to be preferred.
Contamination with moisture will greatly decrease long term
stability of solid peptides. A vial containing a peptide should be
allowed to warm to room temperature prior to being opened. After
removing the desired quantity, the vial should be re-sealed,
preferably under an atmosphere of dry inert gas, and then returned
to cold storage.
Choice of container
An ideal container for peptide manipulation should
be clean, chemically inert, optically clear, strong and available
in an appropriate size. Glass and plastic vials are generally
satisfactory for the purpose, however, care does need to be taken
with plastic vials when organic solvents are to be used.
Polypropylene vials are both strong and chemically inert but if
high visibility is required glass is a better option. Please
appreciate that peptides in solution can and do adsorb to many
materials. This may occur to varying extents being dependent upon
factors such as constituent amino acids, vial material, and peptide
concentration. At high dilution it is possible to lose large
percentages of peptide due to adsorption to surfaces thereby
grossly distorting subsequent results. Use of high quality
specialist glass and polypropylene vials can lessen this
problem.
Peptide dissolution
There is no ideal solvent that will solubilise all
peptides whilst maintaining their integrity and being compatible
with biological assays. It may prove necessary to use a series of
increasingly powerful solvents until the peptide dissolves. For
peptides with a solubility problem the following guidelines may
prove of help.
Approach 1:
In general, attempt to dissolve peptides in sterile
distilled water or sterile dilute acetic acid (0.1%) solution to
give a stock solution at a higher concentration than that required
for subsequent use. This solution may later be diluted with an
appropriate buffer. If the peptide persists as visible particles,
sonication may prove of help as it improves the rate of
dissolution. If, after sonication, the ’solution’ has gelled, has a
persistent haziness, or has a scum floating on the surface, the
peptide has probably not dissolved but is simply finely
suspended.
Approach 2:
If the peptide remains Insoluble, look at Its amino
acid composition prior to proceeding further. What proportion of
amino acids are hydrophobic (A, C, F, I, L, M, P, V, W, Y) and how
many residues are positively charged (K, R, H, and amino terminus)
or negatively charged (D, E, and carboxy terminus)? What is the
overall net charge at neutral pH? If there is a net charge at
neutral pH, addition of dilute acetic acid (for basic, positively
charged peptides) or dilute aqueous ammonia or ammonium bicarbonate
(for acidic, negatively charged peptides) with further sonication
should greatly aid solubility. The final concentration of acetic
acid or ammonia/ammonium bicarbonate allowable will be determined
by the use to which the peptide is to be finally put. If the
peptide still refuses to dissolve, these volatile buffer systems
may be removed by lyophilisation and alternative solvents tried on
the same peptide sample.
Approach 3:
If the peptide sequence has little or no net charge
at any pH, or if the number of hydrophobic residues approaches 50%
or more, +he chances are +ha+ +he above procedures may prove
inadequate. Addition of acetonitrile, ethanol, dimethylformamide
(DMF) dimethyl sulphoxide (DMSO), or the use of chaotropic salts
such as guanidine hydrochloride or urea should aid the dissolution
of most peptides. The choice will depend largely on the
compatibility of such reagents with the subsequent peptide
application. If it is known that the peptide is slightly soluble in
aqueous solution, it is better to first dissolve it completely in a
small amount of neat acetic acid or DMF and then slowly dilute with
water or buffer rather than to add such solvent progressively to a
suspension of the peptide in aqueous systems
Storage of peptide solutions:
The shelf life of peptide solutions is limited
especially for peptides containing C, M, N, Q, and W. To prolong
the storage life of peptides in solution, sterile buffers with a pH
of around 5-6 should be used. Aliquots should be stored at -20°C or
colder wherever possible. Avoid the use of frost-free freezers,
which vary enormously in temperature during the frequent automatic
defrosting cycles. Repeated freeze-thaw cycles are deleterious to
peptides.
Feedback Note:
28/08/03 -They all seemed to dissolve ok in DEPC treated
water with the exception of NPOA0/0116 ’H-ERVVEQMCITQYERESQAYY-OH’
This needed a small amount of DMSO first and then further diluted
in water