Tirzepatide Molecular Weight, Sequence & CAS Reference

1. Biochemical Overview of Tirzepatide

Tirzepatide is a synthetic 39-amino acid peptide designed as a dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist. Preclinical models indicate that its primary sequence is derived from the native GIP sequence, engineered with specific amino acid substitutions and a lipophilic C20 fatty diacid side chain to enable albumin binding and extended half-life during in vitro and in vivo animal studies.

In modern biochemical research, understanding the precise chemical physical parameters of Tirzepatide is essential for concentration calculations, molarity adjustments, and structural integrity verification. As researchers analyze receptor affinity across target tissue assays, access to exact molecular mass and sequence composition ensures reproducible experimental conditions across independent research trials. For broader investigation of metabolic signaling tools, explore our complete catalog of research peptides.

2. Primary Amino Acid Sequence & Structural Modifications

The primary structure of Tirzepatide comprises 39 amino acids with specific synthetic modifications engineered into the backbone. Notably, it incorporates non-coded amino acids, such as alpha-aminoisobutyric acid (Aib), at strategic positions to resist rapid enzymatic degradation by dipeptidyl peptidase-4 (DPP-4).

The published amino acid sequence (single-letter code) for Tirzepatide is: Y-Aib-EGTFTSDYSI-Aib-LDKIAQKAFVQWLIAGGPSSGAPPPS-NH2.

In addition to the modified primary chain, Tirzepatide features a specialized side chain conjugated to the Lysine residue at position 20. This moiety consists of a C20 fatty diacid attached via a linker containing a gamma-glutamyl (γ-Glu) unit and two 2-(2-(2-aminoethoxy)ethoxy)acetic acid (OEG) spacer units. The carboxyl-terminal amino acid (Serine at position 39) is amidated (-NH2), which confers additional stability against carboxypeptidase cleavage in cell culture and enzymatic incubation setups.

3. Molecular Weight, Chemical Formula & Mass Spectrometry

The neutral empirical formula of free-base Tirzepatide is C225H348N48O68. Based on standard atomic weight calculations, the theoretical monoisotopic mass and average molecular weight are as follows:

Monoisotopic Mass: Approximately 4810.52 Da | Average Molecular Weight: 4813.53 g/mol.

When performing electrospray ionization mass spectrometry (ESI-MS) or matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF), investigators typically observe multiply charged ionic species (such as [M+3H]3+, [M+4H]4+, or [M+5H]5+). Accurate identification of these m/z peaks requires accounting for the conjugated fatty acid moiety and amide C-terminus. For detailed batch-specific analytical spectra and lot-level characterization, researchers can inspect the documentation on our certificate of analysis portal.

4. CAS Registry Number & Official Nomenclature

Chemical Abstract Service (CAS) registration provides a unique numerical identifier for chemical substances, facilitating standardized database indexing and laboratory chemical safety tracking.

CAS Registry Number: 2023788-19-2

IUPAC / Systematic Name: L-tyrosyl-2-methylalanyl-L-alpha-glutamyl-glycyl-L-threonyl-L-phenylalanyl-L-threonyl-L-seryl-L-alpha-aspartyl-L-tyrosyl-L-seryl-Isoleucyl-2-methylalanyl-L-leucyl-L-alpha-aspartyl-L-lysyl-Isoleucyl-L-ala-nyl-L-glutaminyl-L-lysyl(N6-(20-carboxy-1-oxoicosyl)-L-gamma-glutamyl-2-(2-(2-aminoethoxy)ethoxy)acetyl-2-(2-(2-aminoethoxy)ethoxy)acetyl)-L-alanyl-L-phenylalanyl-L-valyl-L-glutaminyl-L-tryptophyl-L-leucyl-Isoleucyl-L-alanyl-glycyl-glycyl-L-prolyl-L-seryl-L-seryl-glycyl-L-alanyl-L-prolyl-L-prolyl-L-prolyl-L-serinamide.

Because synthetic research compounds may be cited under various shorthand acronyms or developmental codes (such as LY3298176), cross-referencing CAS 2023788-19-2 ensures absolute identity verification during literature review and standard operating procedure formulation.

5. Counterion Selection & Net Peptide Content Analysis

During solid-phase peptide synthesis (SPPS) and subsequent reverse-phase high-performance liquid chromatography (RP-HPLC) purification, peptides are eluted using mobile phase modifiers. As a result, lyophilizates exist in salt forms—most commonly trifluoroacetate (TFA) or acetate salts.

It is critical for investigators to distinguish between total lyophilized powder mass and Net Peptide Content (NPC). A 10 mg vial of lyophilized Tirzepatide does not consist of 10 mg of pure peptide base; rather, it contains the target peptide bound to residual counterions (TFA or acetate) and bound hydration moisture. Typically, net peptide content ranges from 80% to 90% depending on the final drying and salt conversion protocols.

For exact molar concentrations in cell assays or microfluidic setups, researchers should utilize the Net Peptide Content stated on the lot-specific COA rather than assuming 100% mass equivalence. To accurately calculate solvent volumes for specific target molarities based on mass and purity, utilize our online reconstitution calculator.

6. Comparative Structural Analysis Across Incretin Mimetics

Understanding how structural differences dictate receptor selectivity requires comparing Tirzepatide against single-agonist and tri-agonist research compounds within the incretin family. In preclinical literature, structural modifications directly alter binding kinetics, enzymatic stability, and hydrophobic interaction profiles.

When comparing dual and multi-receptor peptides, researchers frequently evaluate semaglutide research compounds, which rely on a 31-amino acid backbone derived from GLP-1 with a C18 fatty diacid, against retatrutide sequence formulations, a 39-amino acid triple GIP/GLP-1/glucagon agonist containing a C20 fatty diacid and modified Aib residues. Tirzepatide occupies an intermediate architectural niche, utilizing a GIP-based backbone modified for dual GIP/GLP-1 activity. For specific experimental inquiries regarding dual agonist molecules, consult the technical profile for GIP/GLP-1 dual agonists.

7. HPLC and Mass Spectrometry Quality Specifications

To ensure analytical consistency across cellular, tissue, and molecular research projects, PX1 Research subjects every batch of Tirzepatide to rigorous analytical testing in accredited laboratories. Primary quality parameters evaluated before release include:

Purity Determination (RP-HPLC): Demonstrated single peak purity exceeding 99.0%, ensuring the absence of truncated sequences, deletion peptides, or synthesis byproducts.

Mass Verification (ESI-MS): Confirmation of molecular weight matching theoretical 4813.53 g/mol within ±1 Da standard tolerance.

Endotoxin Testing (LAL Assay): Bacterial endotoxin levels rigorously verified below <0.5 EU/mg, preventing confounding inflammatory responses in cell culture models.

Residual Solvent & Counterion Quantification: Verification of low TFA levels or controlled conversion to acetate salts to prevent cellular toxicity during sensitive in vitro assays. Researchers managing large-scale screening facilities can review account setups via our wholesale portal.

8. Lyophilization, Solvent Compatibility, and Handling Standards

Tirzepatide is supplied as a sterile-filtered, lyophilized cake or powder designed strictly for laboratory research use. Due to its hydrophobic C20 fatty acid side chain, proper reconstitution technique is essential to achieve complete dissolution without inducing peptide aggregation.

Solvent Selection: Lyophilized Tirzepatide demonstrates optimal solubility in standard aqueous research buffers such as Bacteriostatic Water, Sterile Water for Injection, or Phosphate-Buffered Saline (PBS, pH 7.4). For highly concentrated stock solutions, addition of a minimal volume of dimethyl sulfoxide (DMSO) or dilute organic modifier may be evaluated in specific analytical protocols.

Handling Recommendations: Avoid vigorous vortexing or rapid mechanical agitation, as shear stress can induce self-assembly or fibril formation in acylated peptides. Gentle swirling and room-temperature equilibration prior to reconstitution are recommended to maintain peptide integrity. For complete technical documentation on handling and peptide chemistry, visit our centralized peptide research hub.