If you synthesise peptides, your building blocks are protected amino acids — and the two dominant protecting-group strategies are Fmoc and Boc. This primer explains the difference for buyers sourcing building blocks in bulk.
What the protecting groups do
Amino acids have reactive groups that must be temporarily "protected" so the peptide chain assembles in the intended order. The protecting group on the alpha-amino function is removed at each coupling step.
- Fmoc (9-fluorenylmethoxycarbonyl): base-labile — removed under mild basic conditions (typically piperidine). Fmoc chemistry is the most common route in modern solid-phase peptide synthesis (SPPS) because conditions are mild and convenient.
- Boc (tert-butoxycarbonyl): acid-labile — removed with acid (e.g. TFA). Boc chemistry is well established and still used for certain sequences and scales.
What buyers should confirm
- The protecting-group scheme you need (Fmoc, Boc, or Z/Cbz for specific intermediates).
- Side-chain protection (e.g. tBu, Trt, Boc on side chains) matching your synthesis plan.
- Purity, optical purity/chirality, and the CAS number for each building block.
- COA with the assay method, plus MSDS.
Range and availability
A capable supplier offers a broad catalogue of Fmoc-, Boc- and Z-protected natural and unnatural amino acids, fragments and intermediates, so you can source most of a sequence from one place.
WYOO supplies 160+ Fmoc / Boc / Z protected amino acids and synthesis building blocks, with COA and MSDS. Send us your list and we will quote availability, purity and lead time.