Skip to main content
Order by 2 pm ET on a business day, ships that dayFree FedEx 2-Day over $250.00
Bag 0 items
Research library
Metabolic researchSelected research

Sermorelin

The amidated 1-29 fragment of human growth hormone releasing factor, studied through solution structure, protease kinetics, conjugation chemistry and validated separation methods.

For in-vitro research only.Reviewed 2026-09-20

Key findings

  • Nuclear magnetic resonance and molecular dynamics showed the fragment adopting an alpha-helix that spans the whole molecule and becomes more rigid toward the C terminus. [1]
  • Dipeptidyl peptidase IV cleaved the 1-29 amide between Ala2 and Asp3 at about the same initial rate as the full 1-44 amide, so shortening the chain does not remove the proteolytic liability. [2]
  • Capillary electrophoresis with dimethyl-beta-cyclodextrin separated the fragment from CJC-1293, two analogues that differ only in the chirality of a single amino acid. [3]
  • In a validated urine method the fragment and its 3-29 amide metabolite degraded rapidly above 4 degrees C and at pH below 7. [4]

Identity and structure

Sequence span
The 1-29 fragment of human growth hormone releasing factor, prepared as the C-terminal amide [1]
Solution structure
An alpha-helix spanning the length of the peptide in trifluoroethanol solution, increasingly rigid toward the C terminus [1]
Closest analogue
Differs from CJC-1293 only in the chirality of one amino acid, which a chiral capillary electrophoresis method can resolve [3]
Known metabolite
A 3-29 amide metabolite is described in the cited detection work [4]
Form as supplied
Sterile lyophilized powder

Mechanism as studied

The fragment carries the same N-terminal dipeptidyl peptidase IV cleavage site as the parent 1-44 amide, and kinetic work found comparable initial rates for the 1-44, 1-29 and 1-20 amides. Shorter fragments and cyclic lactam analogs were cleaved more slowly, which the authors attributed to binding beyond the scissile bond. [2]

Chemical work on the fragment has focused on extending its life by conjugation rather than by changing the sequence. Mono-PEGylation at Lys12 or Lys21 left the alpha-helix intact, so the activity difference between the two regioisomers was attributed to steric hindrance rather than to a conformational change, and site-specific conjugation at Lys21 produced a material far more resistant to rat plasma, liver and kidney homogenates. [1][5]

Research findings

In vitro
System
Purified human placental dipeptidyl peptidase IV with synthetic growth hormone releasing factor and its 1-44, 1-29, 1-20, 1-11 and 1-3 forms, followed by HPLC
Measured
Initial rates of Ala2-Asp3 cleavage and catalytic parameters for P1-substituted analogs
Reported
Initial rates were about 5 micromol per min per mg for the 1-44, 1-29 and 1-20 amides. Lower activities for the shorter fragments and for cyclic lactam analogs indicated binding beyond the scissile bond. Peptides with D-configuration at P2, P1 or P1 prime were not cleaved, and an alpha-aminobutyric acid side chain at P1 was close to optimal for the enzyme. [2]
Structural
System
The 1-29 amide and two mono-PEGylated regioisomers in trifluoroethanol solution, examined by NMR spectroscopy and molecular dynamics
Measured
Secondary structure shifts, hydrogen and deuterium exchange kinetics, amide proton temperature coefficients, NOE-based molecular models
Reported
All three compounds share an alpha-helix that spans the molecule and becomes more rigid toward the C terminus. Conjugation at Lys12 or Lys21 did not alter that helix, add mobility near the conjugation site or change the amphiphilic organisation of the helix. [1]
Analytical
System
A two-step site-specific conjugation of a 1-29 derivative protected at Tyr1 and Lys12, followed by stability testing in rat plasma, liver and kidney homogenates
Measured
Reaction yield, half-life in each homogenate relative to the unmodified fragment, tissue distribution of the iodine-125 labeled material, residual in-vitro activity
Reported
The two-step method gave about 95 percent of the single Lys21 conjugate, 6.3-fold more than nonspecific conjugation at pH 8.5. Half-lives were 7.0, 25.4 and 16.4 times longer than the unmodified fragment in plasma, liver and kidney homogenates. Liver and kidney distribution fell and the conjugate retained 15 percent of the in-vitro activity. [5]
In vitro
System
The 1-29 amide and three analogues extended at the C terminus with a Gly-Gly-Cys-NH2 spacer and monopegylated with polymers of 750 to 10000 molecular weight; the assayed materials are conjugates rather than the plain fragment
Measured
Growth hormone releasing potency in vitro and duration of activity in pig and mouse models
Reported
All C-terminally pegylated analogs retained high growth hormone releasing potency regardless of polymer molecular weight. Two of them showed a longer duration of activity than their non-pegylated counterparts. [6]
Analytical
System
Urine fortified with the fragment, its metabolite, CJC-1295 and tesamorelin, preconcentrated by ultrafiltration alone and read by nanoLC and high resolution tandem mass spectrometry
Measured
Limits of detection and identification, recovery against immuno-affinity purification, stability against temperature and pH
Reported
Limits of detection were 5 to 25 pg/mL and limits of identification 25 to 50 pg/mL, with recoveries of 59 to 115 percent. The fragment and its metabolite degraded rapidly above 4 degrees C and at pH below 7. [4]
Analytical
System
Four growth hormone releasing hormone analogues separated by capillary zone electrophoresis with dimethyl-beta-cyclodextrin as chiral selector and large volume sample stacking with polarity switching
Measured
Enantiomeric separation of the fragment from CJC-1293, signal enhancement factor, limits of detection in buffer and in desalted urine
Reported
The chiral selector separated the two enantiopeptides for the first time. Limits of detection were 75 to 200 ng/mL. A signal enhancement factor of 640 was reached in desalted spiked urine relative to capillary zone electrophoresis without preconcentration. [3]
Order Sermorelin with the certificate for the lot that ships

Handling for in-vitro work

Aqueous stability in cited work
The fragment and its 3-29 metabolite degraded rapidly above 4 degrees C and at pH below 7 in the cited stability experiments [4]
Storage
Lyophilized material kept at minus 20 degrees C, dark and dry; reconstituted aliquots kept cold and used promptly

Open questions

  • No cited study reports a growth hormone releasing hormone receptor binding constant for the unmodified 1-29 amide, so its receptor affinity is inferred from conjugate bioassays rather than measured directly.
  • Whether a supplied vial holds the 1-29 amide rather than its single-residue stereoisomer CJC-1293 is an analytical identity question; the cited capillary electrophoresis method can resolve the two but was not applied to catalog material.

Human studies of this fragment exist and concern finished formulations; they are out of scope for a research material profile.

Lot records

Check the record for the exact material you order. A published paper and a batch certificate answer different questions.

Read a certificate of analysis ↗

References

  1. Digilio G, Barbero L, Bracco C, et al. NMR structure of two novel polyethylene glycol conjugates of the human growth hormone-releasing factor, hGRF(1-29)-NH2. Journal of the American Chemical Society. 2003.

    PubMed 12643708 · doi:10.1021/ja021264j

  2. Bongers J, Lambros T, Ahmad M, et al. Kinetics of dipeptidyl peptidase IV proteolysis of growth hormone-releasing factor and analogs. Biochimica et biophysica acta. 1992.

    PubMed 1353684 · doi:10.1016/0167-4838(92)90317-7

  3. Otin J, Tran NT, Benoit A, et al. Online large volume sample staking preconcentration and separation of enantiomeric GHRH analogs by capillary electrophoresis. Electrophoresis. 2023.

    PubMed 36787346 · doi:10.1002/elps.202200278

  4. Coppieters G, Deventer K, Polet M, et al. An antibody-free, ultrafiltration-based assay for the detection of growth hormone-releasing hormones in urine at low pg/mL concentrations using nanoLC-HRMS/MS. Journal of pharmaceutical and biomedical analysis. 2022.

    PubMed 35298973 · doi:10.1016/j.jpba.2022.114726

  5. Youn YS, Lee KC Site-specific PEGylation for high-yield preparation of Lys(21)-amine PEGylated growth hormone-releasing factor (GRF) (1-29) using a GRF(1-29) derivative FMOC-protected at Tyr(1) and Lys(12). Bioconjugate chemistry. 2007.

    PubMed 17243755 · doi:10.1021/bc060173z

  6. Campbell RM, Heimer EP, Ahmad M, et al. Pegylated peptides. V. Carboxy-terminal PEGylated analogs of growth hormone-releasing factor (GRF) display enhanced duration of biological activity in vivo. The journal of peptide research : official journal of the American Peptide Society. 1997.

    PubMed 9266480 · doi:10.1111/j.1399-3011.1997.tb01160.x

Publication records fetched from PubMed on 2026-09-20. Profile text reviewed 2026-09-20.