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N-Acetyl Semax Amidate Research Reference

Semax with N-terminal acetyl and C-terminal amide caps · Terminal-capping and analogue-comparison research

Classification

TYPE

Synthetic heptapeptide, N-acetylated and C-amidated

Domain

Neurochemical Research Peptides

Format

Lyophilized reference compound

Quick Specs

Molecular Weight

855.0 g/mol

Purity

≥98% (HPLC)

Storage

−20 °C, desiccated

Appearance

White lyophilized powder

Solubility

Soluble in water

01

Research Overview

N-Acetyl Semax Amidate is Semax (Met-Glu-His-Phe-Pro-Gly-Pro) with an acetyl group on the N-terminus and an amide at the C-terminus. As with N-Acetyl Selank Amidate, capping both ends is designed to make the peptide more resistant to enzymes that trim peptides from their termini.

The ACTH(4–7)-Pro-Gly-Pro core is unchanged. It is supplied as a lyophilized reference material for in vitro research, particularly for comparison with Semax and with Adamax, which carries a bulkier adamantane group in place of the simple amide.

02

Structural & Sequence Context

The peptide keeps Semax’s seven residues and modifies only the ends.

Core sequence
Met-Glu-His-Phe-Pro-Gly-Pro: ACTH(4–7) followed by the stabilising Pro-Gly-Pro tail.

N-terminal acetyl group
Replaces the free N-terminal amine with an acetamide. This blocks aminopeptidases, removes one positive charge and adds 42 Da.

C-terminal amide
Replaces the free C-terminal carboxylate with a carboxamide. This blocks carboxypeptidases, removes one negative charge and lowers the mass by about 1 Da.

Retained weak point
Met1 is still present and remains the main oxidation site.

03

Mechanistic Research Context

Research interest in the capped form is mainly comparative.

Exopeptidase resistance
Blocking both termini is expected to slow breakdown by terminal peptidases, which can be compared directly with Semax in serum or tissue incubations.

Relation to Semax research
Its activity is generally assumed to follow that of Semax, including the neurotrophic signalling studied for the parent peptide, but published data on the capped form itself are limited.

Analogue series
Semax, N-Acetyl Semax Amidate and Adamax together form a series with increasingly modified C-termini, useful for structure–property comparisons.

These points are research context only; no effects are claimed for this material.

04

Laboratory Applications

Analogue comparisons
Paired with Semax and Adamax to study how terminal modifications affect stability, hydrophobicity and activity in vitro.

Peptidase studies
A substrate for measuring internal (endopeptidase) cleavage when terminal routes are blocked.

Oxidation studies
Like Semax, it has a single Met1 oxidation site for stress studies.

05

Stability & Handling

Storage
Store the lyophilized powder at −20 °C, sealed, desiccated and protected from light.

Oxidation
Met1 oxidises in the presence of oxygen, trace metals and light. Minimise air exposure and use degassed buffers for sensitive work.

Reconstitution
Soluble in water and aqueous buffers.

Solutions
Prepare fresh or freeze single-use aliquots, and use low-binding polypropylene tubes.

06

Analytical & Purity Considerations

Analysis must confirm both terminal modifications and monitor Met1.

HPLC
Reversed-phase C18 with a TFA gradient; it usually retains slightly longer than Semax. The Met-sulfoxide form elutes earlier.

Mass spectrometry
Positive-mode ESI shows [M+H]⁺ at m/z 855.4 and [M+2H]²⁺ at m/z 428.2 (monoisotopic). MS/MS confirms the acetyl and amide groups.

Impurity profile
Typical checks include Met1 oxidation (+16 Da), incompletely capped forms (−42 Da or about +1 Da), truncated sequences and counter-ion content.

07

Technical Specifications

Analytical Data & Molecular Properties
Sequence
Ac-Met-Glu-His-Phe-Pro-Gly-Pro-NH₂
Molecular Formula
C₃₉H₅₄N₁₀O₁₀S
CAS Number
2920938-90-3
Molecular Weight
855.0 g/mol
Purity
≥98% (HPLC)
Storage
−20 °C, desiccated, protected from light
Appearance
White lyophilized powder
Solubility
Soluble in water
08

Cross-Referenced Materials

09

Frequently Asked Questions

How does N-Acetyl Semax Amidate differ from Semax?

It has the same seven-residue sequence, with an acetyl group on the N-terminus and an amide at the C-terminus. This makes it about 41 Da heavier (855.0 versus 813.9 g/mol) and removes both terminal charges.

How does it differ from Adamax?

Both are N-acetylated Semax analogues. N-Acetyl Semax Amidate ends in a simple amide, whereas Adamax ends in a bulky adamantane carboxamide group, making Adamax much more hydrophobic and heavier (about 1032 g/mol).

What is its CAS number?

It is listed under CAS 2920938-90-3, with formula C₃₉H₅₄N₁₀O₁₀S.

What is the main stability concern?

Oxidation of Met1 to the sulfoxide (+16 Da). Capping the termini does not protect against this.

Which MS signals identify it?

[M+H]⁺ at m/z 855.4 and [M+2H]²⁺ at m/z 428.2 (monoisotopic), with MS/MS confirming the acetyl and amide groups.

Is N-Acetyl Semax Amidate intended for human or veterinary use?

No. It is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.

10

How to Cite This Reference

N-Acetyl Semax Amidate Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/neurochemical-research-peptides/n-acetyl-semax-amidate/

Available for Research

Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.

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