Research Index: Non-clinical summaries for educational and scientific discussion. Not medical advice.

Research Concepts

Educational guides covering peptide research fundamentals, quality verification methods, and proper handling procedures. Essential reading for laboratory researchers.

What Are Peptides?

Peptides are short chains of 2-50 amino acids linked by peptide bonds, functioning as bioactive signaling molecules that bind receptors, inhibit enzymes, or modulate pathways. Unlike full proteins, their smaller size enables better tissue penetration and high specificity for therapeutic targets with reduced side effects.

Peptide Stability

Peptide stability refers to resistance against chemical degradation (oxidation of Met/Cys/Trp, deamidation of Asn/Gln, hydrolysis at Asp-Pro bonds) and physical degradation (aggregation, precipitation). Key factors: temperature, pH extremes, peroxides from excipients, and metal contamination. Lyophilization enhances stability over solution forms.

Peptide Storage

Optimal peptide storage: lyophilized form at -20°C or below under inert gas (argon/nitrogen), protected from light and moisture. Reconstituted solutions should be aliquoted to avoid freeze-thaw cycles and stored at -20°C short-term or -80°C long-term. Avoid repeated temperature fluctuations.

Peptide Half-Life

Peptide half-life (typically minutes to hours) is limited by renal clearance (<5-6 kDa filtered by glomeruli) and proteolytic degradation (DPP-IV, aminopeptidases). Extension strategies include: D-amino acid substitution, albumin binding (fatty acid conjugation), PEGylation, N/C-terminus modification, and cyclization.

HPLC and Mass Spectrometry Testing

RP-HPLC-MS is the gold standard for peptide analysis: HPLC separates by hydrophobicity (C18 column, water/acetonitrile gradient with TFA or formic acid), while MS confirms identity via m/z molecular weight. Validation criteria: purity Rs≥2.0 resolution, R²≥0.999 linearity, ≤2% RSD precision, 98-102% recovery accuracy.

Interpreting Certificates of Analysis

A COA documents purity (>95% ideal via HPLC with chromatogram), identity (MS molecular weight match), net peptide content (70-90% excluding water/salts/TFA), and endotoxin levels (<1 EU/mg for research). Red flags: missing chromatograms, no MS data, in-house only testing, expired dates. Third-party verification preferred.

• Understand what peptides are and how they differ from other compounds
• Learn proper storage and handling to maintain compound integrity
• Interpret Certificates of Analysis for quality verification
• Understand testing methods like HPLC and Mass Spectrometry
• Make informed decisions for research applications