Fmoc-Gly-Gly-Gly-OH, also known as Fmoc-Gly3-OH or Fmoc-triglycine, is a preassembled three-glycine peptide fragment with an Fmoc-protected N-terminus and free C-terminal carboxylic acid. It is used as a flexible linker building block in peptide synthesis, bioconjugation and antibody-drug conjugate (ADC) linker research.

Public supplier literature specifically describes Fmoc-Gly-Gly-Gly-OH as a lysosomally cleavable linker used in ADC and bioconjugation construction. In practice, cleavage behavior is a property of the final linker architecture and biological context; the protected starting fragment itself is an upstream synthetic intermediate.

Product Information

Triglycine as a Linker Motif

Triglycine provides a short, flexible peptide spacer without charged or bulky side chains. It can be useful when a project needs separation between a targeting element and payload, between two peptide domains, or between a biomolecule and reporter group.

The Fmoc-protected N-terminus supports controlled downstream extension after base-mediated deprotection, while the C-terminal carboxyl group provides a second coupling handle.

ADC and Bioconjugation Relevance

Fmoc-Gly3-OH is sold in the industry as a lysosomally cleavable ADC/bioconjugation linker building block.

However, ADC performance depends on the complete construct: antibody attachment chemistry, payload, neighboring linker groups, plasma stability, intracellular trafficking and lysosomal processing all matter. The Gly3 fragment should therefore be evaluated as one modular component of a larger linker system.

Gly3 vs Gly4 and Gly5

Compared with Gly4 or Gly5, Gly3 is shorter and introduces fewer backbone amides. This can reduce linker length while retaining a flexible glycine-rich segment. Longer oligoglycine fragments may provide additional reach, but there is no universal optimum.

Purchasing and QC Considerations

Confirm chain length, Fmoc protection, free C-terminal acid and exact CAS identity. Oligoglycine fragments can differ by only one Gly residue, so LC/MS or equivalent mass confirmation is particularly useful for lot acceptance.

Product Documents

A Material Safety Data Sheet (MSDS) is available for this product to support laboratory handling, storage and safety assessment.

MSDS_Fmoc-Gly-Gly-Gly-OH_AS4063

Certificates of Analysis (COAs) are batch-specific. Please contact us to request the COA for your product, and we will provide it by email.

Frequently Asked Questions

Is Fmoc-Gly-Gly-Gly-OH used in ADC linker synthesis?

Yes. Public supplier literature identifies it as a lysosomally cleavable linker building block used in ADC and bioconjugation research.

Does Fmoc-Gly3-OH itself undergo an in vitro or in vivo assay?

Normally no. The protected fragment is used to build the final conjugate; cleavage, stability and activity are evaluated on the completed construct.

Why choose Gly3 instead of Gly4 or Gly5?

Gly3 provides a shorter flexible spacer. Selection should be based on the required linker length and performance of the final conjugate.

Related Technical Resources

Explore additional Specialty Peptide Building Blocks for protected fragments, linker motifs and peptide-synthesis intermediates.

For sequence-specific synthesis, protected-fragment assembly and modified peptide projects, see our Chemical Peptide Synthesis service.

Research Use Only.