We report net peptide content, not just purity — so the milligrams you dose aren't padded with water and counter-ion. RP-HPLC purity and ESI-MS identity, on a lot-numbered COA.
Net peptide content, not just purity — RP-HPLC + ESI-MS, lot-numbered COA.
Net peptide content on every lot's COA.
Reading a Peptide HPLC Trace — A 5-Minute Field Guide for Bench Scientists. Read our briefing →
Reading a peptide HPLC trace — a field guide. Read →
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Recombinant 191-residue somatropin (~22 kDa) protein standard
Overview
HGH 191AA is recombinant human growth hormone (somatropin), a 191-amino-acid single-chain polypeptide hormone of the somatotropin family, natively secreted by anterior-pituitary somatotrophs. The recombinant material is expressed in Escherichia coli by recombinant-DNA methods and reproduces the exact primary sequence of endogenous pituitary growth hormone. As a ~22 kDa protein (formula C990H1528N262O300S7, 22124.76 g/mol) it folds into a defined tertiary structure stabilized by intramolecular disulfide bonds, and the somatropin molecule is FDA-approved for growth-hormone deficiency in children and adults among further indications. Lyochem supplies HGH 191AA as a lyophilized reference standard at >=99.0% HPLC, characterized with the orthogonal methods appropriate to a folded recombinant protein rather than a short synthetic peptide. Each lot is assessed for purity and size homogeneity by SDS-PAGE and by SEC, with intact-mass confirmation by ESI-MS against the ~22 kDa theoretical value and sequence coverage by LC-MS/MS peptide mapping. This combination documents both chain identity and the monomeric, correctly sized protein population. CAS 12629-01-5; molecular formula C990H1528N262O300S7.
Applications & buyer fit
GH-axis peptides ship to research labs studying somatotropic-pathway pharmacology, IGF-axis signalling, and pulse vs. sustained-elevation GH biology. Buyers qualifying a new source typically request sequence verification on the first lot, the counter-ion form (acetate by default), and stability data at −20 °C. Blends — the CJC-1295 + Ipamorelin co-formulated lot is the canonical example — are co-lyophilised rather than solution-mixed so the ratio is locked at the lyophilisation step.
Academic Laboratories
Universities, medical schools, and government research institutes qualifying a reference standard for a method-development or in vivo workflow.
Biotech R&D Groups
Preclinical biotech and pharmaceutical discovery teams sourcing characterized peptides for receptor-pharmacology, screening, and method-development campaigns.
Every release ships with its own batch-specific CoA — identity, purity, and the analytical scope agreed at quote stage, tied to the exact lot you receive.
Review a representative batch CoA before you order, so you can confirm the packet matches what your method or sponsor audit needs.
Supplied strictly as a research reagent to research institutions — not a finished dosage form and not for human administration. Buyer qualification runs at the inquiry stage.
Specifications
Documentation available on request
Regulatory note
Supplied by Lyochem as a recombinant-protein reference standard for laboratory research and analytical characterization exclusively. It is not a medicine and is not authorized for any human, clinical, diagnostic, or veterinary use, notwithstanding the approved status of somatropin pharmaceuticals.
Frequently asked questions
At 191 residues and ~22 kDa this is a folded protein, so size-level and aggregation information matters. SDS-PAGE confirms the single ~22 kDa band and flags truncation or higher-mass impurities, while SEC reports the monomer fraction versus aggregate. RP-HPLC, intact ESI-MS, and LC-MS/MS mapping then establish purity and sequence identity, together giving a fuller picture than chromatographic purity by itself.
Intact-mass ESI-MS confirms the overall ~22 kDa species matches the theoretical value, and LC-MS/MS peptide mapping digests the protein and reads back sequence coverage across the 191-residue chain. That maps the observed fragments onto the expected recombinant somatropin sequence rather than inferring identity from a single retention time.