CJC-1295 (no DAC)

A 29-residue amide analog of growth hormone–releasing hormone (1–29) with four substitutions: D-Ala2, Gln8, Ala15 and Leu27. Every value on this page is calculated from the structure shown, by the method and constants in the sources below; measured values for a particular lot are on its certificate of analysis.

Structure

Three-letter code: 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 code: YaDAIFTQSY RKVLAQLSAR KLLQDILSR (lower case: D-amino acids)

• 29 residues
• N-terminus: free amine
• C-terminus: amide
• 1 D-residue

Calculated properties

Calculated from the structure

Property	Value
Molecular formula	C152H252N44O42
Average molecular weight	3,367.95 g/mol
Monoisotopic mass	3,365.8936 Da
Net charge at pH 7	4.0
Isoelectric point	10.95
Molar absorption coefficient, 280 nm	2,980 M−1 cm−1
Hydropathy (GRAVY)	-0.08

Net charge across the pH range

pH 2	pH 4	pH 6	pH 7	pH 8	pH 10	pH 12
6.0	4.9	4.0	4.0	3.8	1.9	-1.6

Composition: Leu 5, Ala 4, Arg 3, Gln 3, Ser 3, Asp 2, Ile 2, Lys 2, Tyr 2, Phe 1, Thr 1, Val 1.

Expected mass spectrometry ions

The protonated ions expected in positive-mode electrospray, from the monoisotopic mass, and the common sodium and potassium adducts. MALDI spectra show mainly [M+H]⁺.

Expected ions (monoisotopic)

Ion	m/z
[M+H]+	3,366.9009
[M+2H]2+	1,683.9541
[M+3H]3+	1,122.9718
[M+4H]4+	842.4807
[M+5H]5+	674.1860
[M+Na]+	3,388.8828
[M+K]+	3,404.8567

Isotope pattern

Natural carbon-13, nitrogen-15, oxygen-18, sulfur-34 and deuterium spread each ion over a cluster of peaks about 1 Da apart (1/z on the m/z scale). For a molecule this size the monoisotopic peak is not the tallest: the most abundant is M+1. A spectrum read at its tallest peak, or a deconvoluted mass from it, sits about 1.00 Da above the monoisotopic mass.

Isotope peaks (relative abundance, most abundant = 100)

Peak	Abundance	Neutral mass	[M+H]+	[M+2H]2+	[M+3H]3+	[M+4H]4+	[M+5H]5+
M (monoisotopic)	54.1	3,365.8936	3,366.9009	1,683.9541	1,122.9718	842.4807	674.1860
M+1	100.0	3,366.8964	3,367.9037	1,684.4555	1,123.3061	842.7314	674.3866
M+2	96.7	3,367.8992	3,368.9065	1,684.9569	1,123.6404	842.9821	674.5871
M+3	64.7	3,368.9020	3,369.9092	1,685.4583	1,123.9746	843.2328	674.7877
M+4	33.7	3,369.9046	3,370.9119	1,685.9596	1,124.3088	843.4834	674.9882
M+5	14.4	3,370.9073	3,371.9146	1,686.4609	1,124.6430	843.7341	675.1887
M+6	5.3	3,371.9099	3,372.9172	1,686.9622	1,124.9772	843.9848	675.3893
M+7	1.7	3,372.9125	3,373.9198	1,687.4635	1,125.3114	844.2354	675.5898

Fragment ions (MS/MS)

Collision-induced fragmentation breaks peptide bonds along the backbone. Fragments that keep the N-terminus are b ions; those that keep the C-terminus are y ions. Reading the ladder confirms the sequence residue by residue. Singly charged monoisotopic values, with doubly charged values beside them. The b ion containing every residue is rarely seen and the y ion containing every residue is the precursor itself, so neither is listed.

b and y ions

b#	b+	b2+	Residue	y+	y2+	y#
1	164.0706	82.5389	Tyr	—	—	29
2	235.1077	118.0575	D-Ala	3,203.8375	1,602.4224	28
3	350.1347	175.5710	Asp	3,132.8004	1,566.9038	27
4	421.1718	211.0895	Ala	3,017.7735	1,509.3904	26
5	534.2558	267.6316	Ile	2,946.7364	1,473.8718	25
6	681.3243	341.1658	Phe	2,833.6523	1,417.3298	24
7	782.3719	391.6896	Thr	2,686.5839	1,343.7956	23
8	910.4305	455.7189	Gln	2,585.5362	1,293.2717	22
9	997.4625	499.2349	Ser	2,457.4776	1,229.2424	21
10	1,160.5259	580.7666	Tyr	2,370.4456	1,185.7264	20
11	1,316.6270	658.8171	Arg	2,207.3823	1,104.1948	19
12	1,444.7219	722.8646	Lys	2,051.2812	1,026.1442	18
13	1,543.7904	772.3988	Val	1,923.1862	962.0967	17
14	1,656.8744	828.9408	Leu	1,824.1178	912.5625	16
15	1,727.9115	864.4594	Ala	1,711.0337	856.0205	15
16	1,855.9701	928.4887	Gln	1,639.9966	820.5019	14
17	1,969.0542	985.0307	Leu	1,511.9380	756.4726	13
18	2,056.0862	1,028.5467	Ser	1,398.8540	699.9306	12
19	2,127.1233	1,064.0653	Ala	1,311.8219	656.4146	11
20	2,283.2244	1,142.1159	Arg	1,240.7848	620.8960	10
21	2,411.3194	1,206.1633	Lys	1,084.6837	542.8455	9
22	2,524.4035	1,262.7054	Leu	956.5887	478.7980	8
23	2,637.4875	1,319.2474	Leu	843.5047	422.2560	7
24	2,765.5461	1,383.2767	Gln	730.4206	365.7139	6
25	2,880.5730	1,440.7902	Asp	602.3620	301.6847	5
26	2,993.6571	1,497.3322	Ile	487.3351	244.1712	4
27	3,106.7412	1,553.8742	Leu	374.2510	187.6292	3
28	3,193.7732	1,597.3902	Ser	261.1670	131.0871	2
29	—	—	Arg	174.1349	87.5711	1

Immonium ions (low-mass markers of the residues present): Ala 44.0495, Ser 60.0444, Val 72.0808, Thr 74.0600, Ile 86.0964, Leu 86.0964, Asp 88.0393, Gln 101.0709, Lys 101.1073, Phe 120.0808, Arg 129.1135, Tyr 136.0757.

What to watch for analytically

Variants this sequence can give, from its chemistry. They are what an HPLC or mass spectrometry result for this peptide is read against; none is a statement about a particular lot. Where synthesis variants come from is explained in How synthetic peptides are made.

Sequence-specific variants

Variant	Mass change	Why
Glutamine deamidation	+0.984 Da	Glutamine at positions 8, 16 and 24 can also deamidate, much more slowly than asparagine.
Stereochemistry	0 Da	1 residue is in the D-configuration by design. An epimer at any position has the same mass, so stereochemical purity is a chromatographic question.
C-terminal amide	free-acid variant +0.984 Da	The C-terminus is an amide. The corresponding free acid, from synthesis or hydrolysis, differs by +0.984 Da, close to the isotope spacing, so it needs a resolved spectrum to tell apart.
Synthesis-related variants	e.g. +252.082 Da (Pbf), minus a residue (deletion)	As for any synthetic peptide, deletion sequences and incompletely deprotected forms can occur; on arginine, a residual Pbf protecting group adds 252.082 Da.

Sources & Further Reading

1. Prohaska T, Irrgeher J, Benefield J, Böhlke JK, Chesson LA, Coplen TB, et al. Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure and Applied Chemistry 2022;94(5):573–600. doi:10.1515/pac-2019-0603
2. Wang M, Huang WJ, Kondev FG, Audi G, Naimi S. The AME 2020 atomic mass evaluation (II). Tables, graphs and references. Chinese Physics C 2021;45(3):030003. doi:10.1088/1674-1137/abddaf
3. Rice P, Longden I, Bleasby A. EMBOSS: the European Molecular Biology Open Software Suite. Trends in Genetics 2000;16(6):276–277. doi:10.1016/S0168-9525(00)02024-2
4. Pace CN, Vajdos F, Fee L, Grimsley G, Gray T. How to measure and predict the molar absorption coefficient of a protein. Protein Science 1995;4(11):2411–2423. doi:10.1002/pro.5560041120
5. Kyte J, Doolittle RF. A simple method for displaying the hydropathic character of a protein. Journal of Molecular Biology 1982;157(1):105–132. doi:10.1016/0022-2836(82)90515-0
6. Meija J, Coplen TB, Berglund M, Brand WA, De Bièvre P, Gröning M, et al. Isotopic compositions of the elements 2013 (IUPAC Technical Report). Pure and Applied Chemistry 2016;88(3):293–306. doi:10.1515/pac-2015-0503
7. Roepstorff P, Fohlman J. Letter to the editors: proposal for a common nomenclature for sequence ions in mass spectra of peptides. Biomedical Mass Spectrometry 1984;11(11):601. doi:10.1002/bms.1200111109
8. Biemann K. Contributions of mass spectrometry to peptide and protein structure. Biomedical and Environmental Mass Spectrometry 1988;16(1–12):99–111. doi:10.1002/bms.1200160119
9. Geiger T, Clarke S. Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation. Journal of Biological Chemistry 1987;262(2):785–794. doi:10.1016/S0021-9258(19)75855-4
10. Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharmaceutical Research 2010;27(4):544–575. doi:10.1007/s11095-009-0045-6
11. D'Hondt M, Bracke N, Taevernier L, Gevaert B, Verbeke F, Wynendaele E, et al. Related impurities in peptide medicines. Journal of Pharmaceutical and Biomedical Analysis 2014;101:2–30. doi:10.1016/j.jpba.2014.06.012

Cosmic Peptides. (2026, October 25). CJC-1295 (no DAC): peptide reference entry. Cosmic Peptides Research Library. Retrieved October 26, 2026, from https://cosmicpeptides.com/research/peptides/cjc-1295-no-dac

@misc{cosmicpeptides_research_peptides_cjc_1295_no_dac,
  author       = {{Cosmic Peptides}},
  title        = {CJC-1295 (no DAC): peptide reference entry},
  howpublished = {Cosmic Peptides Research Library},
  year         = {2026},
  month        = oct,
  url          = {https://cosmicpeptides.com/research/peptides/cjc-1295-no-dac},
  urldate      = {2026-10-26},
  note         = {Last reviewed 2026-10-25}
}

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PB  - Cosmic Peptides
PY  - 2026
DA  - 2026/10/25
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Y2  - 2026/10/26
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