Product Overview

Fmoc-Gly-OH is the Fmoc-protected form of glycine and one of the most fundamental building blocks in peptide synthesis.

Unlike most proteinogenic amino acids, glycine has no side-chain carbon beyond hydrogen and therefore contains no stereogenic α-carbon. As a result, glycine does not present the conventional α-carbon racemization issue encountered with chiral amino acids.

No side-chain protecting group is required.

This simple structure makes Fmoc-Gly-OH widely applicable in:

• conventional peptide synthesis

• flexible peptide linkers

• glycine-rich sequences

• peptide libraries

• spacer design

• cyclic and modified peptides

Applications in Peptide Synthesis

Fmoc-Gly-OH in Fmoc-SPPS

Fmoc-Gly-OH requires only α-amino protection because glycine has no functional side chain requiring protection.

The free carboxyl group is activated and coupled to the resin-bound amine. After incorporation, Fmoc is removed under standard basic conditions to expose the amino terminus for further chain elongation.

Its lack of side-chain protection makes Fmoc-Gly-OH chemically simpler than many protected amino-acid building blocks.

Explore the broader family of Standard Fmoc-Amino Acids.

Glycine Backbone Properties

Glycine is unique among the 20 standard proteinogenic amino acids because its side chain is simply hydrogen.

This produces two important consequences.

First, glycine is achiral, meaning conventional L/D stereochemical designation does not apply.

Second, glycine provides greater backbone conformational freedom than most amino acids.

Depending on sequence context, this can be useful for:

• flexible linkers

• turns and loops

• reducing local steric crowding

• connecting functional peptide domains

• allowing conformational rearrangement around binding regions

However, additional flexibility is not always beneficial. In a bioactive peptide, replacing a conformationally restricted residue with glycine may increase entropy and reduce the population of a binding-competent conformation.

Glycine as a Peptide Linker and Spacer

Glycine is frequently combined with residues such as serine to construct flexible linker sequences.

Its small size makes it useful where the objective is to separate two functional regions without introducing a bulky or strongly interacting side chain.

Examples include:

• peptide–protein linkers

• multifunctional peptide constructs

• fluorescent peptide designs

• conjugated peptides

• cyclic peptide linker regions

For these applications, linker length should be optimized according to the required geometry rather than simply adding multiple Gly residues without structural rationale.

For projects involving linker design or modification, see Custom Peptide Synthesis.

Analytical Considerations

Because glycine contains no stereocenter, chiral purity is generally not a meaningful specification for Fmoc-Gly-OH in the same way that D-isomer content is for L-amino-acid building blocks.

More relevant quality parameters include:

• chemical purity

• identity

• water content

• residual starting materials

• Fmoc-related impurities

• coupling performance

Product Documents

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

MSDS_Fmoc-Gly-OH_AS1216

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

Related Technical Resources

Learn more in Solid-Phase Peptide Synthesis (SPPS): A Practical Guide.

Explore Amino Acids & Peptide Building Blocks.

Browse Standard Fmoc-Amino Acids.

For complete peptide projects, see Custom Peptide Synthesis.

Research Use Only