H-Gly-Gly-Phe-Gly-PAB; CAS 2632341-94-5 is a peptide-PAB linker intermediate built around the Gly-Gly-Phe-Gly motif and a para-aminobenzyl (PAB) spacer. It is intended for research on cleavable linker architecture, linker assembly and bioconjugation chemistry rather than as a free bioactive peptide.

The product is best understood as a modular synthetic intermediate: the peptide sequence provides an enzyme-responsive segment in relevant linker designs, while the PAB unit is commonly used as a self-immolative spacer in drug-linker chemistry. Lot-specific identity and purity should be confirmed before incorporation into a conjugation workflow.

Product Information

Role in Cleavable Linker Research

H-Gly-Gly-Phe-Gly-PAB is a research linker precursor containing the Gly-Gly-Phe-Gly peptide sequence and a PAB self-immolative spacer. In linker-development studies, enzymatic cleavage of the peptide segment and subsequent spacer fragmentation should be treated as distinct design steps. Cleavage behavior is system-dependent and should be validated with the intended enzyme, substrate context, buffer conditions, and analytical method.

Distinguishing the PAB Precursor from Activated Linkers

This material is not the same as MC-GGFG-PAB-PNP, PAB-PNP, or a payload-conjugated linker. Those products contain additional reactive or activated groups. Match the exact structure to the planned linker-assembly step before ordering.

Procurement and QC Considerations

Confirm the exact peptide sequence, PAB termination, molecular mass and HPLC/MS identity. PAB-containing linker intermediates can be confused with activated PNP carbonates or maleimide-containing derivatives, which are different products and should not share a CAS or specification.

Related materials can be reviewed under impurity and research standards.

For broader sequence or project work, see peptide linker synthesis.

Linker Identity and Reactive-State Control

Peptide-PAB intermediates should be ordered against the exact sequence and terminal chemical state. PAB-OH, activated PAB derivatives and payload-bearing linkers are different materials and can show similar naming across supplier catalogs.

For linker assembly, lot-specific HPLC and mass data are useful for confirming the intended intermediate before conjugation. If a prepared solution will be stored or reused, solution stability should be established under the selected solvent and concentration conditions.

Product Documents

MSDS - H-Gly-Gly-Phe-Gly-PAB (AS4129)

The Safety Data Sheet provides product identification, laboratory handling guidance, exposure controls, transport information and safety information for research use.

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

What is H-Gly-Gly-Phe-Gly-PAB?

It is Gly-Gly-Phe-Gly-PAB-OH; GGFG-PAB-OH, a defined research compound with sequence or structural identity Gly-Gly-Phe-Gly-PAB.

Is this a complete antibody-drug conjugate linker?

No. It is a peptide-PAB linker intermediate and does not by itself include every conjugation handle, activation group or payload component used in a complete ADC linker.

Why is the exact PAB termination important?

PAB-OH, PAB-PNP and other activated PAB derivatives are chemically different intermediates with different downstream reactivity.

Research Use Only.