Solid-phase peptide synthesis

Solid-phase peptide synthesis (SPPS) is a chemical manufacturing method introduced by Bruce Merrifield in 1963. It builds peptides by anchoring the growing chain to insoluble resin beads, then adding amino acids one at a time. Because the peptide stays on the solid support, excess reagents and byproducts can be removed through wash cycles. SPPS is commonly automated, typically uses Fmoc-based chemistry, and works well for sequences up to 50-60 amino acids long.

SPPS is the manufacturing process rather than an analytical test

SPPS is the production method used to create peptides, not a test that evaluates their quality. Synthesis errors matter in lab reports because they create impurities that later testing must detect. Incomplete coupling or deprotection can produce deletion peptides missing one or more amino acids. Other issues include racemization, side-chain rearrangements, chemical contamination, and aggregation in longer sequences.

Laboratory tests used to evaluate SPPS outputs

• HPLC separates the target peptide from byproducts to measure purity.
• Mass spectrometry checks molecular weight to verify peptide identity.
• Amino acid analysis determines net peptide content after accounting for residual water or salts.

Distinguishing SPPS from analytical products and liquid-phase synthesis

SPPS should not be confused with analytical tests such as HPLC or mass spectrometry. SPPS creates the peptide, while those tests evaluate the final product. It is also distinct from liquid-phase or solution-phase peptide synthesis, where the peptide chain is built entirely in liquid without a solid support.

Sources

1. Liquid-Phase Peptide Synthesis (LPPS): A Third Wave for the Preparation of Peptides
2. Concept and early development of solid-phase peptide synthesis
3. Liquid Chromatography-High Resolution Mass Spectrometry for Peptide Drug Quality Control - PMC
4. Automated solid-phase peptide synthesis to obtain therapeutic peptides - PMC
5. Fundamental Aspects of SPPS and Green Chemical Peptide ...
6. Challenges and Perspectives in Chemical Synthesis of Highly ...
7. WHO good practices for pharmaceutical quality control ...
8. Knowledge Hub - Bachem
9. Peptide Purity & Yield Optimizing in SPPS | PurePep Blog
10. Mastering Peptide Synthesis: Coupling Reagents, Protecting Groups, and Solid-Phase Peptide Synthesis
11. Solid-Phase vs Liquid-Phase Peptide Synthesis | Adesis
12. Peptide synthesis
13. HPLC and Mass Spectrometry for Peptide Validation
14. Solid-Phase vs. Solution-Phase Peptide Synthesis
15. Reference Standards to Support Quality of Synthetic Peptide Therapeutics
16. Purification of Peptides from Solid-Phase Peptide Synthesis with RP-HPLC
17. Merrifield Solid-Phase Peptide Synthesis Explained: Definition, Examples, Practice & Video Lessons
18. Peptide Testing: HPLC & Mass Spec Purity Guide | Apex