Research Guidelines
Research peptides are sensitive. Structural integrity depends on consistent, careful handling from the moment a vial leaves storage. Work in a clean, draft-free environment — a laminar flow hood or biosafety cabinet is ideal — and wear appropriate PPE throughout.
Repeated freeze-thaw cycles damage peptide bonds and promote aggregation; they also accelerate oxidation of residues such as methionine and tryptophan, so avoid them. Use low-binding polypropylene tubes to limit adsorption losses. Before opening a lyophilised vial, give it a brief centrifuge spin to consolidate the powder and stop it dispersing on unsealing.
Lyophilised peptides should be stored at -20°C or below in a frost-free freezer. Sequences containing cysteine, methionine, or tryptophan are particularly prone to oxidative degradation — store these under inert gas (argon or nitrogen) or with desiccant. Keep all peptide stock away from light; UV exposure drives photo-oxidation. Low relative humidity matters too, so keep vials in a sealed desiccator when not in active use.
Reconstituted solutions are considerably less stable than lyophilised stocks. Aliquot immediately, store at -80°C where possible, and aim to use within 30 days. Always let frozen vials equilibrate to room temperature before opening — condensation contamination is a real and avoidable problem.
Check the peptide datasheet before you reconstitute anything. Solubility varies significantly by sequence.
Acidic peptides — those with a high proportion of Asp or Glu residues — typically dissolve readily in aqueous buffers or dilute acetic acid (0.1% v/v). Basic peptides, rich in Lys or Arg, often need dilute ammonium hydroxide (0.1% v/v). Hydrophobic sequences are trickier; dissolve these first in an organic co-solvent such as DMSO or acetonitrile, then dilute into aqueous buffer.
Add solvent gently to the lyophilised powder. Aggressive vortexing promotes aggregation. If dissolution is incomplete, use a water bath sonicator in 30-second intervals rather than increasing mechanical agitation. Record the final concentration and solvent composition in your laboratory notebook straight away, not later.
Concentration accuracy drives reproducibility. The calculation is straightforward: divide the total peptide mass (mg) by the molecular weight (g/mol, listed on the CoA) to get moles, then divide by your reconstitution volume in litres to get molarity.
Worked Example
5 mg ÷ 1,500 g/mol = 3.33 µmol → reconstituted in 1 mL = 3.33 mM stock solution
Always check purity from the third-party Certificate of Analysis and factor it into your calculation where precision matters. Prepare serial dilutions from a master stock rather than repeatedly handling concentrated material. Every calculation, lot number, and dilution step needs to be in a traceable laboratory record — not just for compliance, but because you will need it later.
All peptides supplied by Premio Peptides are for in vitro research use only. They must not be administered to humans or animals outside of formally approved research protocols. Treat every research peptide as a potentially hazardous compound.
Minimum PPE during weighing and reconstitution: nitrile gloves, lab coat, safety spectacles. Where aerosolisation is possible — weighing lyophilised powder being the obvious case — use a half-face respirator with a P3 filter, or work inside a fume hood.
Dispose of peptide waste, used vials, and contaminated consumables according to your institution’s chemical waste policy and UK COSHH regulations. Safety Data Sheets must be on file and accessible to everyone working in the lab.
Good documentation is not optional. It underpins reproducible, publishable research — and it protects you.
For every peptide used, record: supplier name and product code, lot number, date of receipt, storage location, date of reconstitution, solvent system, final concentration, and the date of each aliquot use. Retain all Certificates of Analysis — Premio Peptides provides third-party HPLC and mass spectrometry CoAs with every order — and attach copies to the relevant experiment records.
If you use an electronic laboratory notebook, tag entries with the peptide lot number for rapid cross-referencing. Records should be kept for a minimum of ten years, in line with good laboratory practice (GLP) principles and UK Research Integrity Office (UKRIO) guidance.
-20°C is the standard minimum. For long-term archival of sensitive sequences, -80°C is preferable. Peptides containing easily oxidised residues — Cys, Met, Trp — benefit from desiccant or inert gas storage. Let vials reach room temperature before opening to prevent moisture ingress.
No more than three before degradation becomes a measurable concern. The straightforward way to avoid the problem: aliquot reconstituted stocks into single-use volumes immediately after preparation, freeze at -80°C, and thaw only what you need for each session.
Start with an organic co-solvent — DMSO or acetonitrile work well. Prepare a concentrated stock in DMSO (typically 10–50 mg/mL), then dilute slowly into your aqueous buffer with gentle mixing. Keep the final DMSO concentration in working solutions below 1% to avoid solvent-related assay interference; 0.1% is better where possible.
Divide the peptide mass in milligrams by its molecular weight in g/mol to get millimoles, then divide by the reconstitution volume in millilitres to get millimolar (mM) concentration. Molecular weight is on the Premio Peptides Certificate of Analysis. If purity is below 98%, adjust the effective mass to get a corrected figure.
Stability depends on sequence, but 30 days is a reasonable working limit for reconstituted aqueous solutions. Peptides in acidic or basic buffers may degrade faster than those in neutral PBS. For sequences with known susceptibility to hydrolysis or oxidation, use within 7–14 days and verify integrity by HPLC if quantitative accuracy is critical.
No. All peptides are manufactured and sold strictly for in vitro laboratory research. They are not sterile pharmaceutical preparations, are not approved for clinical, veterinary, or human use, and must not be administered to any living organism outside a formally approved, institutionally governed research protocol.
All Premio Peptides orders placed before 2pm, Monday to Friday, are dispatched the same day. Every order includes third-party HPLC and mass spectrometry Certificates of Analysis.