Peptide research library

What are research peptides?

Peptides are short chains of amino acids joined by peptide bonds, usually between 2 and 50 residues long. Research peptides are synthetic versions made by solid-phase peptide synthesis (SPPS), in which amino acids are added one at a time to a growing chain anchored on a resin, then cleaved, purified by preparative HPLC and freeze-dried.

Laboratories use them as defined reagents: to probe receptor binding, map signaling pathways, act as reference standards, or test hypotheses in cell-based and other preclinical models. Because a peptide’s activity depends on its exact sequence, the identity and purity of each batch matter as much as the compound itself.

Sources: Solid Phase Peptide Synthesis. I. The Synthesis of a Tetrapeptide (Journal of the American Chemical Society, 1963) · Advances in Fmoc solid-phase peptide synthesis (J Pept Sci, 2016)

How to read a Certificate of Analysis

A Certificate of Analysis (COA) reports what was measured for one production batch. On our COAs, look for:

• Batch number and test date, which should match your vial and order.
• Total purity by HPLC: the share of the main peak in the chromatogram, reported as a percentage. Our specification is 98% or higher.
• Single and total impurities: the largest individual impurity peak and the sum of all impurity peaks.
• Identity by mass spectrometry (MS): confirms the measured molecular mass matches the expected sequence.
• Water and TFA content: residual moisture and trifluoroacetate counter-ion left from purification.
• Endotoxin, bioburden and heavy metals: contaminant screens reported against set limits.

Every published report is in the COA Library.

Sources: Q6B Specifications: Test Procedures and Acceptance Criteria for Biotechnological/Biological Products (ICH / U.S. Food and Drug Administration, 1999) · Related impurities in peptide medicines (J Pharm Biomed Anal, 2014)

HPLC and mass spectrometry, briefly

High-performance liquid chromatography (HPLC) pushes a dissolved sample through a packed column. Different molecules travel at different speeds and leave the column at different retention times, producing a chromatogram of peaks. Purity is calculated from the area of the main peak relative to all peaks detected.

Mass spectrometry (MS) ionizes the sample and measures the mass-to-charge ratio of the ions. Comparing the measured mass with the theoretical mass of the sequence confirms that the main peak is the intended peptide. Together, HPLC answers “how pure?” and MS answers “is it the right molecule?”

Sources: Analysis of synthetic peptides by high-performance liquid chromatography (Methods Enzymol, 1997) · Implementation of a single quad MS detector in routine QC analysis of peptide drugs (J Pharm Anal, 2016)

Lyophilization and storage

Lyophilization (freeze-drying) removes water from a frozen peptide solution under vacuum, leaving a dry cake or powder. Dry peptides are far more stable than peptides in solution, which is why research peptides ship lyophilized.

General laboratory practice is to store sealed lyophilized vials frozen or refrigerated, protected from light and moisture, and to let a vial reach room temperature before opening to limit condensation. Once reconstituted, peptides degrade faster; aliquoting avoids repeated freezing and thawing. Storage temperatures for each compound are listed on its profile. Reconstitution solution is sold separately.

Sources: Lyophilization and development of solid protein pharmaceuticals (Int J Pharm, 2000)

What “research use only” means

Research use only (RUO) means a product is supplied for laboratory research and is not intended for human or veterinary use or for any diagnostic or therapeutic procedure. RUO products are not drugs, and they are not evaluated or approved by the FDA for any use.

Our research profiles summarize published laboratory and preclinical literature about each compound for scientific reference. They do not describe or recommend any use outside the laboratory, and we publish identity and specification data only.

Sources: Distribution of In Vitro Diagnostic Products Labeled for Research Use Only or Investigational Use Only (U.S. Food and Drug Administration (guidance for industry and FDA staff), 2013)