Modified GRF (1-29)

1 Identity

GHRH analogues. A synthetic 29-residue C-terminally amidated peptide carrying four substitutions against the native fragment, one of them a D-residue. No acylation, no albumin-binding conjugate, no disulfide, no PEG, no metal.

Contains Modified GRF (1-29) / CJC-1295 No DAC + Ipamorelin

Sequence

H-Tyr-D-Ala-Asp-Ala-Ile-Phe-Thr-Gln-Ser-Tyr-Arg-Lys-Val-Leu-Ala-Gln-Leu-Ser-Ala-Arg-Lys-Leu-Leu-Gln-Asp-Ile-Leu-Ser-Arg-NH2; one-letter with the D-residue marked, Y-(D-A)-DAIFTQSYRKVLAQLSARKLLQDILSR-NH2. Twenty-nine residues; the C-terminus is A primary carboxamide, not A free acid. Four substitutions against native human GHRH(1-29), and all four are omitted by the trade descriptions of this material: D-alanine at position 2, which is what makes a chiral method mandatory rather than optional; Gln at position 8 (native Asn); Ala at position 15 (native Gly); and Leu at position 27 (native Met). The LEU27 substitution removes the only sulfur atom in the native sequence, which is the single most useful compositional handle on this molecule: any sulfur in an elemental result or an isotope pattern indicates sermorelin-family contamination. Two Tyr and one Phe give a usable 280 nm signal, unlike several neighboring records in this catalog.

Molecular formula

C152H252N44O42 (C-terminal amide, the specified article). Des-amido (C-terminal free acid) form C152H251N43O43. Sermorelin / GRF(1-29) amide C149H246N44O42S. CJC-1295 with DAC C165H269N47O46.

Average mass

3,367.954 Da (C152H252N44O42) on IUPAC 2021 abridged conventional atomic weights; listings commonly print 3,367.95. Two independent commercial sources print the same figure, one as MW 3367.95 and one as 3367.954 with the full sequence printed. On a 3.4 kDa peptide the average mass moves by up to 0.05 Da between atomic-weight tables, so lots are verified against the monoisotopic figure, not against this one. Comparators: des-amido free acid 3,368.94 (+0.98); sermorelin 3,357.93 (-10.02, and it contains one sulfur); CJC-1295 with DAC 3,647.25 (+279.30). Salt: acetate or trifluoroacetate, with net peptide content on a trifluoroacetate lot typically 75-85 percent, so a declared 5 mg vial is 3.8 to 4.3 mg of peptide.

Monoisotopic mass

3,365.89358 Da neutral (C152H252N44O42). Working ions: [M+3H]3+ m/z 1,122.97180; [M+4H]4+ m/z 842.48067; [M+2H]2+ m/z 1,683.95407. Comparators: des-amido free acid 3,366.87759 (+0.98401); sermorelin 3,355.81870; CJC-1295 with DAC 3,645.01548.

Salt / variant note

(1) sermorelin / GRF(1-29) amide (human), YADAIFTNSYRKVLGQLSARKLLQDIMSR-NH2, C149H246N44O42S, 3,357.93 average / 3,355.81870 monoisotopic, CAS 86168-78-7, available as a reference standard in the acetate salt form. 10.02 Da lighter than this article and it contains one sulfur; the sulfur isotope pattern and the mass defect both distinguish it cleanly on a high-resolution instrument, so a lot substituted this way is detectable by arithmetic. (2) (D-Ala2)-GRF(1-29) amide (human), the mono-substituted analogue: it is an exact stereoisomer of sermorelin, identical formula C149H246N44O42S, identical 3,357.93 average and 3,355.81870 monoisotopic. No mass method of any resolution separates it from sermorelin; only chiral amino acid analysis does. It is a purchasable catalog item, which makes this a real substitution route and not a theoretical one. (3) the L-Ala2 diastereomer of this article itself: identical formula C152H252N44O42, identical 3,367.95 average and 3,365.89358 monoisotopic, identical retention on an achiral column within method noise. A lot synthesized with L-Ala at position 2 instead of D-Ala is a different molecule that NO mass spectrum, NO achiral HPLC purity method and NO amino acid analysis can detect. This is the substitution the Marfey requirement exists for and it is why that requirement is written as non-waivable. (4) des-amido (C-terminal free acid) form, C152H251N43O43, 3,368.94 / 3,366.87759, +0.98 Da - the routine incomplete-amidation or hydrolysis failure, not a hypothetical, and a single-quadrupole instrument reporting '3368' cannot distinguish it from the parent. (5) CJC-1295 with DAC, C165H269N47O46, 3,647.25 / 3,645.01548, +279.30 Da, sold under an overlapping head name; the trade misnomer runs in both directions - 'CJC-1295 no DAC' on a vial of this article, and 'CJC-1295' on a vial that may be either molecule. (6) blend vials: 'CJC-1295 (no DAC) + Ipamorelin' is a widely sold single vial containing two different peptides. A single purity figure on a two-peptide vial is arithmetically meaningless and such a vial cannot be released against any single-entity specification. (7) Aspartimide and iso-aspartate species at Asp3 and Asp25, isobaric with the parent and separable only chromatographically. (8) Salt form: acetate or trifluoroacetate, moving net peptide content by 15 to 25 percentage points.

2 Class & testing panel

Form

Single article

Testing panel

P3 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Published literature exists and, under the designation used here, it is thin. The substitution chemistry of GHRH(1-29) analogues is described in the peptide-chemistry literature of the 1980s and 1990s from the Salk Institute program (Rivier, Ling and colleagues), which is the source of all four substitutions in this molecule. Under this designation the literature is rodent and in-vitro pharmacology, a small number of livestock and veterinary studies, and no registered controlled human trial identified on ClinicalTrials.gov. The human clinical literature in this family attaches to two other molecules - the native 1-29 fragment marketed in the United States until 2008, and the DAC conjugate cataloged separately - and does not transfer to this analogue.

4 Storage & specification

Storage

Lyophilized white powder, sealed under nitrogen in an amber borosilicate serum vial with a fluoropolymer-faced stopper and an aluminum overseal, non-sterile with no sterility claim. Labeled condition -20 degrees C plus or minus 5 degrees C, desiccated, protected from light. With MET27 replaced by Leu the principal remaining solid-state degradation routes are aspartimide formation at ASP3 and ASP25 and hydrolysis of the C-terminal amide, both of which are slowed by low water activity - so the desiccant condition is a release-relevant instruction and not packaging convenience, and the inert headspace is specified for the container rather than for oxidation control, since the sequence has no oxidation-labile residue left in it. Sealed vials are equilibrated to room temperature before opening.

Shelf life

Provisional 24 months at -20 degrees C plus or minus 5 degrees C, desiccated, on a 0/3/6/9/12/18/24-month protocol with a 6-month accelerated arm at 25 degrees C / 60 percent relative humidity. Iso-aspartate content is the expected retest-limiting attribute and is measured at every timepoint alongside the des-amido free acid; gross purity is not expected to be the limiting number and a stability study that trends only gross purity would miss both. The certificate prints the retest date as the lot's QA release date plus that interval.