Ac-His(Trt)-OH is N-alpha-acetyl, imidazole-Trt-protected L-histidine. The alpha amino group is permanently acetylated for the intended synthesis step, while the histidine imidazole is protected with Trt to control side-chain reactivity.

This protection pattern makes Ac-His(Trt)-OH particularly useful for N-terminal Ac-His installation, protected peptide fragments and sequence-defined acetylated peptide standards. It is not a routine internal Fmoc monomer because the alpha nitrogen cannot be deprotected for continued chain elongation.

Product Information

Why Use a Pre-Acetylated Histidine?

When the final peptide specifically requires N-acetyl-His at the terminus, a pre-acetylated building block fixes that terminal chemistry before coupling. This can be useful in route development, peptide standard preparation and synthesis of fragments where post-assembly N-terminal acetylation is undesirable or impractical.

Histidine Coupling and Stereochemical Considerations

Histidine derivatives can be sensitive to activation-dependent epimerization. The Trt-protected imidazole helps control side-chain chemistry, but coupling reagent, base, preactivation time and temperature should still be selected carefully when stereochemical integrity matters.

Application Scope

Ac-His(Trt)-OH is suited to modified peptide synthesis, N-terminal acetylation studies, protected fragment assembly and preparation of peptide reference materials. Final deprotected peptides may be used in biochemical, binding or cellular studies where terminal acetylation is part of the molecular design.

Product Documents

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

MSDS_Ac-His-Trt--OH_AS4039

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 Ac-His(Trt)-OH interchangeable with Fmoc-His(Trt)-OH?

No. Ac-His(Trt)-OH has an acetylated alpha amino group and is generally a terminal building block, whereas Fmoc-His(Trt)-OH has a removable alpha-amino protecting group for normal chain elongation.

What does Trt protect in this molecule?

Trt protects the histidine imidazole nitrogen during peptide synthesis.

Why pay attention to histidine epimerization?

Histidine can undergo activation-dependent stereochemical erosion under some coupling conditions, so reagent/base choice and activation time matter.

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