IGF-DES Molecular Weight: Molecular Mass, Sequence & Research Guide

Introduction

Understanding the IGF-DES molecular weight is an important part of identifying and characterizing this truncated IGF-1 peptide in laboratory research.

IGF-DES is commonly referred to as Des(1-3)IGF-1, Des(1-3)IGF-I, or IGF-1 DES. It is a truncated form of human insulin-like growth factor 1 in which the first three residues of the mature peptide—Gly-Pro-Glu (GPE)—are absent. The resulting peptide contains 67 amino acids. The original scientific literature describes Des(1-3)IGF-I as a naturally occurring truncated variant of IGF-I.

For analytical purposes, it is important to distinguish between different ways of reporting molecular mass. Current analytical references list a theoretical monoisotopic mass of approximately 7,365.72 Da, while average-mass calculations are approximately 7,371 Da.

Therefore, a concise answer to the primary SEO question is:

IGF-DES molecular weight is approximately 7.37 kDa, with the exact reported value depending on whether monoisotopic or average molecular mass is being used.

This guide explains the molecular weight, sequence, molecular formula, structural characteristics, analytical testing, HPLC, mass spectrometry, COA documentation, and research-use considerations associated with IGF-DES.

What Is IGF-DES?

IGF-DES is a shortened form of human IGF-1.

The designation Des(1-3)IGF-1 indicates that residues 1 through 3 of the mature IGF-1 chain are absent.

Those three residues are:

Glycine — G
Proline — P
Glutamic acid — E

Together:

GPE

After removal of this N-terminal tripeptide, the resulting IGF-DES molecule contains 67 amino acids rather than the 70 amino acids found in mature human IGF-1. The published literature identifies Des(1-3)IGF-I as a truncated IGF-I variant lacking the N-terminal Gly-Pro-Glu sequence.

This structural difference is central to understanding why different IGF-related peptides can have different molecular masses.

IGF-DES Molecular Weight at a Glance

Property	IGF-DES
Common name	IGF-DES
Alternative name	Des(1-3)IGF-1
Alternative designation	Des(1-3)IGF-I
Peptide length	67 amino acids
Parent molecule	Human IGF-1
Removed residues	Gly-Pro-Glu (GPE)
Approximate molecular weight	~7.37 kDa
Theoretical monoisotopic mass	7,365.7188 Da
Approximate average mass	~7,371 Da
Molecular formula used for monoisotopic calculation	C317H508N92O95S7
Structural feature	Three intramolecular disulfide bonds
Research context	Peptide and IGF molecular research

The 7,365.7188-Da value is reported as the theoretical monoisotopic mass in current analytical records, while compound-level references list an average mass around 7,371 Da.

What Is the Exact IGF-DES Molecular Weight?

The answer depends on the mass convention.

Monoisotopic Molecular Mass

A current analytical reference calculates the theoretical monoisotopic mass of IGF-1 DES as:

7,365.7188 Da

This value is calculated from the molecular formula:

C317H508N92O95S7

The same reference reports an experimentally observed neutral mass of approximately 7,365.74 Da for one analyzed batch.

Average Molecular Mass

Average molecular mass is slightly higher:

approximately 7,371 Da

An analytical compound reference lists an average mass of approximately 7,371.00 Da, while a recent batch COA reports 7,371.48 g/mol as the theoretical average mass for the molecular formula stated on that certificate.

Why Are There Two Numbers?

The difference does not necessarily indicate different peptides.

It reflects the distinction between:

Monoisotopic mass
Average molecular mass
Molecular formula used
Oxidation/disulfide state
Salt or counter-ion form
Analytical calculation method

For SEO and general research documentation, ~7.37 kDa is the most useful simplified description.

For analytical work, however, researchers should specify the exact mass convention.

IGF-DES Molecular Formula

A current analytical reference gives the molecular formula used for the theoretical monoisotopic calculation as:

C317H508N92O95S7

From this formula, the reported theoretical monoisotopic mass is:

7,365.7188 Da.

Other databases or certificates may report molecular formulas using a different molecular convention, particularly when discussing average mass, molecular hydration, counter-ions, or specific preparation forms.

For that reason, a product page should avoid presenting a single formula as universally applicable to every possible physical form without identifying the calculation basis.

IGF-DES Peptide Length

IGF-DES contains:

67 amino acids

The parent mature human IGF-1 molecule contains 70 amino acids. Removing the N-terminal GPE sequence gives:

70 − 3 = 67 amino acids

The sequence begins with the fourth residue of mature IGF-1.

IGF-DES sequence

TLCGAELVDALQFVCGDRGFYFNKPTGYGSSSRRAPQTGIVDECCFRSCDLRRLEMYCAPLKPAKSA

The 67-residue sequence and the removal of the GPE residues are documented in research references describing Des(1-3)IGF-I.

IGF-DES vs. Full-Length IGF-1 Molecular Weight

Comparing IGF-DES with mature IGF-1 helps explain the molecular-weight difference.

Mature IGF-1

Mature human IGF-1 contains 70 amino acids.

IGF-DES

IGF-DES contains 67 amino acids because the N-terminal GPE sequence has been removed.

The mass difference between the two forms is therefore associated with removal of those three residues, with the exact observed difference also depending on how molecular mass and molecular form are calculated.

Analytical references identify full-length IGF-1 as approximately +343 Da relative to IGF-DES in mass-spectrometric impurity tracking.

This provides a useful analytical fingerprint when distinguishing full-length IGF-1 from the Des(1-3) variant.

Why Molecular Weight Matters for IGF-DES Research

Molecular weight is one of several important parameters used to characterize peptide research materials.

1. Identity Confirmation

Expected molecular mass can be compared with experimentally observed mass to support compound identification.

2. Mass-Spectrometry Analysis

Mass spectrometry can measure peptide ions in multiple charge states. The observed charge-state distribution can be deconvoluted to estimate the neutral molecular mass.

3. Sequence Verification

Theoretical mass calculated from a proposed sequence can be compared with experimental measurements.

4. Detection of Related Species

Mass differences can help identify related components.

For example, analytical references describe:

Full-length IGF-1 at approximately +343 Da
Over-truncated Des(1-4)IGF-1 at approximately −87 Da
IGF-DES dimer at approximately +7,365.7 Da

relative to the principal IGF-DES molecular species.

5. Quality Documentation

Molecular-mass information can form part of a batch-specific COA or analytical report.

IGF-DES Mass Spectrometry

Mass spectrometry is particularly useful for confirming the expected molecular mass of a peptide.

For IGF-DES, electrospray ionization can produce multiple positively charged molecular ions.

One current analytical report lists observed charge states including:

The most intense signal in that report was the 7+ charge state, with an observed m/z close to the theoretical value. The corresponding deconvoluted neutral mass was approximately 7,365.74 Da.

This illustrates why a laboratory report may display an m/z value rather than simply showing 7,365 Da.

Molecular Mass vs. m/z

These terms should not be confused.

Molecular mass:
The calculated or experimentally determined mass of the neutral molecule.

m/z:
Mass-to-charge ratio measured for a particular ion.

A multiply charged peptide can therefore produce an m/z value substantially lower than its total molecular mass.

IGF-DES HPLC Analysis

HPLC provides complementary information to mass spectrometry.

Reverse-phase HPLC (RP-HPLC) can be used to examine the chromatographic profile of an IGF-DES research material.

An HPLC analysis may provide:

Retention time
Main peak area
Relative area percentage
Related-substance peaks
Chromatographic purity
Analytical method information

Current analytical records demonstrate that IGF-DES can be evaluated using chromatographic and mass-spectrometric methods together.

Importantly:

HPLC purity does not equal molecular identity.

A high-percentage HPLC peak indicates chromatographic purity under the stated analytical conditions. Mass spectrometry can provide additional evidence about molecular mass and identity.

For stronger analytical characterization, laboratories may therefore use:

RP-HPLC + MS + sequence or peptide mapping

rather than relying on one test alone.

IGF-DES Purity

Purity values should always be tied to a specific analytical method and batch.

For example, publicly available analytical reports show variation between individual lots and analytical records. One 2025 report lists a principal IGF-DES peak at 97.77% area, while other analytical reports show higher values.

A recent publicly available COA also reports 99.27% RP-HPLC purity for its particular IGF-1 DES batch. That number applies to that specific certificate and should not automatically be presented as a universal specification for every IGF-DES material.

For SEO content, appropriate wording is:

“Purity should be evaluated using the applicable batch-specific analytical report or COA.”

This is more scientifically precise than making a blanket purity claim.

IGF-DES COA: Important Analytical Information

A Certificate of Analysis (COA) can help researchers evaluate a particular lot.

A useful IGF-DES COA may include:

Product Identification

Product name
Lot or batch number
Catalog number
Date of analysis

Molecular Information

Molecular formula
Molecular mass
Expected mass
Observed mass

HPLC

Analytical method
Retention time
Main peak area
Reported purity
Related substances

Mass Spectrometry

Ionization method
Charge-state information
Observed m/z
Calculated m/z
Mass deviation

Additional Testing

Depending on the material and intended research application, documentation may include other quality-control measurements.

The important principle is that batch-specific documentation should be used for batch-specific claims.

IGF-DES Molecular Structure

IGF-DES retains the characteristic structural framework associated with the IGF-1 family while lacking the N-terminal GPE sequence.

The sequence contains multiple cysteine residues, allowing the oxidized peptide to form intramolecular disulfide bonds.

The three-disulfide structure is relevant when interpreting analytical mass data because the molecular form being measured affects how theoretical mass should be calculated.

This is particularly important when comparing:

Reduced peptide
Oxidized peptide
Correctly folded material
Disulfide-scrambled species
Aggregated material

Analytical records specifically identify disulfide-scrambled isomers and aggregated species as distinguishable components in IGF-DES testing.

IGF-DES Research Applications

IGF-DES has been studied as a truncated IGF-I variant in molecular and cellular research.

The scientific literature describes Des(1-3)IGF-I as a naturally occurring truncated IGF-I form and discusses its altered interaction with IGF-binding proteins compared with full-length IGF-I.

Research contexts can include:

IGF molecular biology
Peptide structure-function studies
IGF-binding-protein research
Receptor-signaling investigations
Cell-based research models
Protein and peptide characterization
Analytical chemistry
Comparative IGF peptide studies

These descriptions refer to research contexts, not an indication that IGF-DES is approved for therapeutic use.

Research-Use-Only Wording

For a U.S.-targeted research website, the following copy can be used:

Research Use Only: IGF-DES is presented as a laboratory research material for qualified scientific research, peptide characterization, analytical testing, and controlled in-vitro research workflows. It is not represented as a drug, dietary supplement, diagnostic product, or medical treatment. It is not intended for human or veterinary use. Researchers are responsible for following applicable institutional, laboratory, safety, and regulatory requirements.

This wording keeps the page focused on scientific characterization rather than therapeutic claims.