DAC linker raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-07-04 and is reviewed periodically as new material appears.
Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.
CJC-1295 is a synthetic peptide analog of growth hormone-releasing hormone, constructed on the 29-amino-acid fragment designated GRF(1-29). The name began as an internal development code during the 1990s and later spread through research supply catalogs and discussion forums. The molecule does not occur in nature; its sequence is engineered rather than isolated from tissue. Two related compounds are sold under this single label, and they differ by one appended chemical group that strongly influences how long the peptide remains in circulation.
The dividing feature between the two forms is a maleimide-based drug affinity complex, abbreviated DAC. In the DAC-bearing version, a linker attaches the peptide to serum albumin after administration, and that association slows removal from plasma. The version lacking DAC appears in catalogs as MOD GRF(1-29) or tetrasubstituted GRF(1-29). Because informal writing treats both as one item, comparisons drawn from such sources routinely blend measurements taken from two molecules with substantially different behavior.
Two related forms appear under the CJC-1295 name. The simpler analogue, commonly written as modified GRF(1-29), carries the four substitutions but no additional conjugation. The second form attaches a maleimidopropionic acid linker to a lysine residue, a modification frequently called the drug affinity complex. That linker reacts with the free thiol on serum albumin to form a covalent bond. Because albumin has a long residence time in blood, the conjugated peptide stays in circulation far longer than the unconjugated analogue.
Receptor level activity follows the canonical GHRH pathway. The peptide binds the GHRH receptor, a class B G protein coupled receptor on somatotroph cells of the anterior pituitary. Binding raises intracellular cyclic AMP, which promotes calcium entry and the release of growth hormone into the bloodstream. Because the molecule acts at the same receptor as the endogenous hormone, its effect is superimposed on the natural pulsatile rhythm rather than replacing it. Whether sustained receptor occupation leads to desensitization is not fully settled.
CJC-1295 belongs to a class of synthetic peptides modeled on growth hormone releasing hormone, a forty-four amino acid signal produced by the hypothalamus. The compound is built from the first twenty-nine residues of the natural sequence, with four substitutions introduced at positions 2, 8, 15 and 27. These changes were designed to slow enzymatic breakdown while preserving receptor activation. The result is a peptide that is shorter than native GHRH and considerably more resistant to ordinary clearance pathways in circulation.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | Analog of growth hormone-releasing hormone |
| Chain length | 29 amino acids | Based on the GRF(1-29) fragment |
| Appearance | White to off-white lyophilized powder | Common research supply form |
| Solubility | Soluble in water and aqueous buffers | Powder requires reconstitution before use |
| Typical storage | −20 °C or below | Kept away from light and moisture |
CJC-1295 is a synthetic peptide designed to mimic growth hormone-releasing hormone (GHRH), the endogenous signal that prompts the pituitary gland to release growth hormone. The compound is a modified fragment of the natural hormone, spanning the first twenty-nine amino acids of GHRH with several substitutions that slow enzymatic breakdown. Two variants circulate in research settings: one carrying a drug affinity complex (DAC) and one without it. The DAC-free form is frequently labelled Mod GRF(1-29) in catalogs and discussion forums.
The peptide binds GHRH receptors on somatotroph cells within the anterior pituitary, triggering a signalling cascade that increases growth hormone secretion. Its improved resistance to dipeptidyl peptidase IV degradation distinguishes it from the parent hormone. In the DAC-bearing version, a maleimide group reacts with a cysteine residue on serum albumin, forming a covalent bond that keeps the peptide in circulation far longer. That albumin attachment is the central design feature separating the two research variants.
Lyophilised powder is the usual supplied form. The material is hygroscopic, so vials are typically equilibrated to room temperature before opening in order to prevent condensation on the contents. Long-term storage is generally described at minus twenty degrees Celsius or colder, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of soluble material. A reconstituted solution is considerably less stable than the dry powder and is normally kept refrigerated for short periods only.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography combined with mass spectrometry. The chromatographic separation resolves the target peptide from truncation products and from species carrying oxidised residues, while mass measurement confirms the expected molecular mass. Because the two common variants differ by roughly 280 daltons, a mass determination distinguishes them unambiguously. Purity is often quoted as a percentage of total peak area, although that figure depends on the detection wavelength and the integration method applied.
Reported half-lives differ widely between the two variants and between species. Values for the albumin-binding form are usually expressed in days, while the unconjugated form is measured in minutes to a few hours. Sampling schedules, assay sensitivity, and route of administration all influence the numbers, which limits direct comparison across studies. Whether sustained receptor occupancy produces different downstream effects from pulsatile stimulation remains an open question in the published work. Claims about relative potency should therefore be read alongside the specific study design that produced them.
=== Manufacturing === Packaging lines can have a variety of equipment types: integration of automated systems can be a challenge. All aspects of food production, including packaging, are tightly controlled and have regulatory requirements. Uniformity, cleanliness and other requirements are needed to maintain Good Manufacturing Practices. Product safety management is vital. A complete Quality Management System must be in place. Hazard Analysis and Critical Control Points is one methodology which has been proven useful. Verification and validation involves collecting documentary evidence of all aspects of compliance. Quality assurance extends beyond the packaging operations, through distribution and cold chain management.
India is a megadiverse country, a term employed for 17 countries that host high biological diversity and contain many species indigenous, or endemic, to them. India is the habitat for 8.6% of all mammals, 13.7% of bird species, 7.9% of reptile species, 6% of amphibian species, 12.2% of fish species, and 6.0% of all flowering plant species. Fully a third of Indian plant species are endemic. India also overlaps four of the world's 34 biodiversity hotspots, or regions that display significant habitat loss in the presence of high endemism. India's densest forests, such as the tropical moist forest of the Andaman Islands, the Western Ghats, and Northeast India, occupy about 3% of its land area. Moderately dense forest, whose canopy density is between 40% and 70%, occupies 9.39% of India's land area. It predominates in the temperate coniferous forest of the Himalayas, the moist deciduous sal forest of eastern India, and the dry deciduous teak forest of central and southern India. India has two natural zones of thorn forest, one in the Deccan Plateau, immediately east of the Western Ghats, and the other in the western part of the Indo-Gangetic plain, now turned into rich agricultural land by irrigation, its features no longer visible. Among the Indian subcontinent's notable indigenous trees are the astringent Azadirachta indica, or neem, which is widely used in rural Indian herbal medicine, and the luxuriant Ficus religiosa, or peepul, which is displayed on the ancient seals of Mohenjo-daro, and under which the Buddha is recorded in the Pali canon to have sought enlightenment.
== Clinical significance == Band neutrophils are an intermediary step prior to the complete maturation of segmented neutrophils. Polymorphonuclear neutrophils are initially released from the bone marrow as band cells. As the immature neutrophils become activated or exposed to pathogens, their nucleus will take on a segmented appearance. An increase in the number of these immature neutrophils in circulation can be indicative of an infection for which they are being called to fight against, or some inflammatory process. The increase of band cells in the circulation is called bandemia and is a "left shift" process. Blood reference ranges for neutrophilic band cells in adults are 3 to 5% of white blood cells, or up to 0.7 billion/L. An excess may sometimes be referred to as bandemia.
This differential equation is the classic equation of motion of a charged particle in a vacuum. Together with the particle's initial conditions, it determines the particle's motion in space and time. It immediately reveals that two particles with the same m/Q ratio behave in the same way. This is why the mass-to-charge ratio is an important physical quantity in those scientific fields where charged particles interact with magnetic or electric fields.
Sources: en.wikipedia.org
As of July 2024, lisdexamfetamine is the only pharmacotherapy approved by the US Food and Drug Administration (FDA) and the Therapeutic Goods Administration for BED. Evidence indicates that its effectiveness in treating BED may be partially due to a psychopathological overlap with attention deficit hyperactivity disorder, a cognitive-control disorder that also benefits from treatment with lisdexamfetamine. Medical reviews of randomized controlled trials have established that lisdexamfetamine, administered at doses between 50 and 70 mg, is safe and effective for treating BED. These reviews consistently report fewer weekly binge eating episodes. Furthermore, a meta-analytic systematic review included a 12-month study showing the medication was effective for a long period of time. Two reviews have found lisdexamfetamine to be superior to placebo in several secondary outcomes, including persistent binge eating cessation and reductions in obsessive-compulsive binge eating symptoms, body weight, and triglycerides. Lisdexamfetamine is a pharmacologically inert prodrug that confers its therapeutic effects for BED after conversion to its active metabolite, dextroamphetamine, which acts in the central nervous system. Dextroamphetamine increases the availability of dopamine and norepinephrine in the prefrontal cortex, which makes major decision-making for the body. Lisdexamfetamine, like all pharmaceutical amphetamines, possesses direct appetite suppressant effects, which may be therapeutically beneficial for BED and its associated comorbidities.
^ Pesek, J. J.; Matyska, M. T.; Prabhakaran, S. J. (2005). "Synthesis and characterization of chemically bonded stationary phases on hydride surfaces by hydrosilation of alkynes and dienes". Journal of Separation Science. 28 (18): 2437–43. doi:10.1002/jssc.200500249. PMID 16405172. ^ Pesek, J. J.; Matyska, M. T.; Gangakhedkar, S.; Siddiq, R. (2006). "Synthesis and HPLC evaluation of carboxylic acid phases on a hydride surface". Journal of Separation Science. 29 (6): 872–80. doi:10.1002/jssc.200500433. PMID 16830499. ^ Hemström, P.; Irgum, K. (2006). "Hydrophilic interaction chromatography". Journal of Separation Science. 29 (12): 1784–821. doi:10.1002/jssc.200600199. PMID 16970185. ^ C. Kulsing, Y. Nolvachai, P.J. Marriott, R.I. Boysen, M.T. Matyska, J.J. Pesek, M.T.W. Hearn, J. Phys. Chem B, 119 (2015) 3063-3069. ^ J. Soukup, P. Janas, P. Jandera, J. Chromatogr. A, 1286 (2013) 111-118
=== Lyophilized === Lyophilized drugs are stored in vials, cartridges, dual chamber syringes, and prefilled mixing systems. Lyophilization, or freeze drying, is a process that removes water from a liquid drug creating a solid powder, or cake. The lyophilized product is stable for extended periods of time and could allow storage at higher temperatures. In protein formulations, stabilizers are added to replace the water and preserve the structure of the molecule. Before administration, a lyophilized drug is reconstituted as a liquid before being administered. This is done by combining a liquid diluent with the freeze-dried powder, mixing, then injecting. Reconstitution usually requires a reconstitution and delivery system to ensure that the drug is correctly mixed and administered.
Sources: en.wikipedia.org
No. It is a laboratory-synthesized analog built on a fragment of the natural hormone. The natural peptide is shorter-lived and lacks the stabilizing substitutions found in the synthetic version.
DAC stands for drug affinity complex, a chemical group that binds the peptide to serum albumin. The binding slows clearance and lengthens the time the molecule stays in plasma compared with the unmodified analog.
Because two distinct molecules are discussed under one informal label. The albumin-binding version clears over several days, while the form without that group clears within roughly half an hour. Mixing results from both creates inconsistent figures.
The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.