High purity peptides - professional synthesis for laboratory studies

The process of preparing the peptide requires multi-step peptide synthesis and purification, to obtain high-purity products for use in experimental research.

Step 1: Activation of amino acid monomers
Peptide synthesis begins with the preparation of amino acid monomers necessary for the construction of polypeptides. These monomers are activated in research laboratories to enable their subsequent assembly into peptide sequences. Activation of the amino acids allows intermediate forms to be obtained ready for further synthesis steps and the formation of more complex peptides.

Step 2: Synthesis of the tripeptides Tyr-Gly-Gly-Phe-Leu and Lys-Glu-Val-Lys-Asp
In the next step, the amino acids are combined to produce two tripeptides, Tyr-Gly-Gly-Phe-Leu and Lys-Glu-Val-Lys-Asp. In research laboratories, this process is carried out in stages, by gradually combining the amino acids into specific sequences until the target tripeptides are obtained, which can be further combined with other peptide fragments to build the complete polypeptide structure.

Step 3: Ligation of the C-terminus of the peptide fragment
In this step, the ligation of peptide fragments takes place to create a more complex peptide structure. The intermediates resulting from this ligation are then purified, which allows for high purity of the test material and ensures its stability in further synthesis steps.

Step 4: Ligation of further peptide fragments
The next step involves combining the previously obtained tripeptides with other peptide fragments to form larger sequences. This process in research laboratories requires repeated purification and quality control to ensure that the final product has the correct peptide structure and purity.

Step 5: Determination of the N-end
The final step in the synthesis involves the introduction of the N-terminal labeling of the peptide for research purposes. This allows the molecular structure to be identified and confirmed in research laboratories. This process also allows further investigation of the biological properties of the peptide in experimental models.

Summary
All stages of peptide synthesis in research laboratories involve multi-step peptide synthesis, purification and quality control to produce high-purity formulations. These materials serve exclusively for experimental and scientific research and should not be interpreted as medicinal or therapeutic products.

Research peptides as HPLC standards - application and laboratory procedure

The reagent can be used in analytical and R&D laboratories as a reference material (standard/standard) for the preparation of standard solutions, quality control and validation of determination methods. The product is used, inter alia, in quantitative and qualitative analysis by chromatographic methods, in particular HPLC/UPLC, as well as in methodological work including:

  • preparation of calibration curves and working solutions,
  • tests for repeatability and reproducibility of the method,
  • verification of selectivity, linearity and sensitivity (LOD/LOQ),
  • consistency control of results as part of routine tests,
  • studies on the stability of the analyte in solution and in the matrix.

The reagent is intended for professional use in a laboratory setting, in accordance with good laboratory practice (GLP) and current health and safety procedures.

Procedure for use in HPLC as a standard/standard (SOP - example)

1) Objective

Preparation of standard solution (stock) and working solutions of the analyte for analysis by the method of HPLC for identification and/or quantification.

2) Scope

The procedure concerns the preparation of a standard from a solid reagent (powder/crystalline) or liquid standard and the making of solutions for the calibration curve.

3) Reagents and materials
  • reagent under test (standard/standard): [name, purity, cat.no./CAS].
  • solvent: [e.g. methanol / acetonitrile / water / buffer]., HPLC quality
  • HPLC mobile phase: [composition].
  • syringe filters 0.22 µm or 0.45 µm (PTFE/NYLON/PVDF - by solvent)
  • volumetric flasks (e.g. 10, 50, 100 mL), automatic pipettes, analytical balances (0.1 mg)
  • HPLC vials with inserts (if required)
4) Equipment
  • HPLC system with detector [UV/DAD/FLD/MS].
  • stirrer/sonicator (optional)
  • pH meter (if buffers used)

5) Safety

Work with gloves and safety goggles. Use fume cupboard with volatile solvents. Follow the safety data sheet (SDS) for the reagent and solvents.

A. Preparation of stock solution

A1) Calculations

Target stock concentration: Cₛ = [e.g. 1000 µg/mL].
Flask volume: V = [e.g. 10.00 mL].
Weight required: m = Cₛ × V (including units)
If you specify purity (assay), e.g. 99.5%:
m_correction = m / 0,995

A2) Implementation
  1. Label the measuring flask: „Stock - [name].”, date, person, solvent.
  2. Dare [m_corrections] mg standard on an analytical balance.
  3. Transfer quantitatively to a volumetric flask [V mL].
  4. Add approx. 70-80% by volume of solvent, dissolve (mixing/sonication).
  5. Fill up to the mark with the same solvent and mix thoroughly.
  6. If the solution is to be run on HPLC: filter through a filter 0.22/0.45 µm into the HPLC vial (if there is a risk of particles).

Practical remarks

  • If the analyte is poorly soluble, use a solvent mixture (e.g. MeOH:H₂O) or consider gentle heating (if stability permits).
  • Avoid long sonication for sensitive substances (risk of degradation).

B. Preparation of working solutions and calibration curve

  1. On the basis of the stock, prepare a series of working solutions in the range of e.g.
    [1, 5, 10, 25, 50, 100 µg/mL]. (or any other required by the method).
  2. Dilute in a solvent compatible with the mobile phase or in a diluent (e.g. mobile phase, MeOH:H₂O).
  3. Describe each level: concentration, date, person.
  4. (Optional) prepare a QC control standard in the middle of the range, e.g. [25 µg/mL]..

C. HPLC parameters - template to be entered

  • Column: [e.g. C18, 150 × 4.6 mm, 5 µm].
  • Column temperature: [e.g. 30°C].
  • Mobile phase: [A: water + 0.1% formic acid; B: ACN].
  • Programme: isocratic [e.g. 60:40]. or gradient [description].
  • Flow: [e.g. 1.0 mL/min].
  • Injection volume: [e.g. 10 µL].
  • Detection: [e.g. UV 254 nm / DAD 200-400 nm / MS].
  • Analysis time: [e.g. 10 min].

D. Sequence of injections (example)

  • Blank (diluent)
  • Medium standard (system suitability/retention check)
  • Calibration curve from lowest to highest concentration
  • QC (every 10 samples, for example)
  • Test samples
  • Final standard (drift control)

E. Acceptance criteria (example)

  • Linearity of the curve: R² ≥ 0,995 (or by method)
  • Repeatability: RSD of area for n=5 injections of standard ≤ 2.0%
  • Compatibility of retention: retention time deviation ≤ 2% (or by method)
  • QC within ± 10% nominal value (or according to validation)

F. Storage of solutions

  • Store stock and working solutions in [2-8°C ], in the dark, in sealed vials.
  • Recommended duration of use: [e.g. 14-48 days]. (unless otherwise indicated by stability studies)
  • Avoid repeated freezing/thawing.
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