This is a working overview of Drug affinity complex, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-08-31. Anything still debated is marked as such rather than presented as settled.
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.
Downstream of growth hormone, the liver and other tissues increase production of insulin-like growth factor 1, a mediator of many growth-promoting effects. Studies have documented elevated levels of both hormones after dosing, and the rise from the long-acting form persists longer than that produced by shorter-acting analogues. What remains unclear is whether sustained elevation of these markers translates into meaningful clinical benefit, and whether prolonged exposure carries risks that short trials could not detect.
CJC-1295 acts at the growth hormone-releasing hormone receptor, a G-protein-coupled receptor found on somatotroph cells in the anterior pituitary. Binding triggers a rise in cyclic AMP and calcium entry, which promotes release of stored growth hormone. Because the peptide mimics the body's own releasing hormone, it amplifies existing secretory pulses rather than driving continuous output. The size of the response therefore depends partly on the subject's own hormonal rhythm and feedback state.
| Property | Value | Notes |
|---|---|---|
| Peptide class | Synthetic GHRH analogue | Built on a 29 residue sequence |
| Primary target | GHRH receptor (GHRHR) | Class B G protein coupled receptor |
| Unconjugated half life | Minutes | Limited by protease degradation |
| Key modification | Four residue substitutions | Positions 2, 8, 15 and 27 |
| Common synonym | Modified GRF(1-29) | Usually denotes the form without DAC |
The drug affinity complex is a maleimidopropionic acid group attached to a lysine side chain. It reacts with the free thiol of cysteine-34 on circulating albumin, forming a covalent bond. This conjugation keeps the peptide in the bloodstream and shields it from rapid renal filtration and proteolysis. Reported circulation half-lives for the albumin-bound form fall in the range of roughly six to nine days in early human studies.
Binding to GHRH receptors on pituitary somatotroph cells triggers cyclic AMP signaling and stimulates growth hormone synthesis and release. Because the peptide acts upstream of the pituitary, effects are mediated through endogenous growth hormone rather than direct receptor activation in peripheral tissues. Increases in insulin-like growth factor 1 are generally described as a downstream consequence. Most published human exposure data come from small early-stage studies, and the clinical significance of the pharmacokinetic profile remains incompletely characterized.
The peptide backbone includes a D-alanine at position two, which resists cleavage by dipeptidyl peptidase IV, and several other substitutions that reduce degradation. Its molecular weight is roughly 3.4 kDa without the linker and about 3.6 kDa with it. The molecule is water soluble and is normally supplied as a lyophilized powder. Precise sequence and mass values depend on which variant is described, so technical documents usually state the exact form being referenced.
CJC-1295 is a synthetic peptide designed as a long-acting analogue of growth hormone-releasing hormone (GHRH). Its structure derives from the first 29 amino acids of native GHRH, a fragment often called GRF(1-29). Four substitutions were introduced to slow enzymatic breakdown and extend activity relative to the natural sequence. The compound was developed by ConjuChem as part of a broader effort to improve the pharmacokinetic profile of peptide hormones. It is studied in laboratory and clinical research settings rather than appearing as a naturally occurring substance.
The albumin-binding version stays in circulation for days, because covalent attachment to serum albumin shields the peptide from rapid filtration and degradation. Reported half-lives for this form fall in the range of several days. The version without the linker is cleared in minutes, with estimates often near thirty minutes in animal work. These figures come from small studies and vary with assay method, species, and route, so they are best read as approximate rather than fixed constants.
Studies in this area generally track growth hormone pulses, insulin-like growth factor 1 concentrations, and occasionally body composition endpoints. Most published human data come from early, small trials, and questions about long-term effects remain open. Whether repeated exposure alters pituitary responsiveness over time is not settled. Analytical work relies on immunoassays for the hormones and on mass spectrometry for the peptide itself, because the two measurements answer different questions.
== Clinical presentation == Patients with hemoglobin H disease present with chronic hemolytic anemia that ranges in severity from mild to moderate disease. Anemia is the most common presenting symptom of patients with HbH disease. Other common clinical features include jaundice, splenomegaly, hepatomegaly, and gallstones. All of these symptoms are related to the destruction of the red blood cells in the spleen and the associated increased hemoglobin metabolism. Patients with non-deletional HbH disease are more likely to be symptomatic and have severe disease presentation when compared to individuals with deletional HbH disease. Disease presentation varies from asymptomatic individuals to neonatal growth retardation and death in the most severe cases. Death in the neonatal period occurs due to the severe anemia resulting in hydrops fetalis. Patients most often present initially due to hemolytic episodes that occur during times of infection or inflammation. During these episodes, patients may develop hemolytic crisis, in which there is a rapid drop in the hemoglobin due to increased red blood cell destruction.
internal validation or cross-validation (actually, while extracting data, cross validation is a measure of model robustness, the more a model is robust (higher q2) the less data extraction perturb the original model); external validation by splitting the available data set into training set for model development and prediction set for model predictivity check; blind external validation by application of model on new external data and data randomization or Y-scrambling for verifying the absence of chance correlation between the response and the modeling descriptors. The success of any QSAR model depends on accuracy of the input data, selection of appropriate descriptors and statistical tools, and most importantly validation of the developed model. Validation is the process by which the reliability and relevance of a procedure are established for a specific purpose; for QSAR models validation must be mainly for robustness, prediction performances and applicability domain (AD) of the models. Some validation methodologies can be problematic. For example, leave one-out cross-validation generally leads to an overestimation of predictive capacity. Even with external validation, it is difficult to determine whether the selection of training and test sets was manipulated to maximize the predictive capacity of the model being published. Different aspects of validation of QSAR models that need attention include methods of selection of training set compounds, setting training set size and impact of variable selection for training set models for determining the quality of prediction.
For example, global proteome-wide substitutions of natural amino acids with fluorinated analogs have been attempted in E. coli and B. subtilis. A complete tryptophan substitution with thienopyrrole-alanine in response to 20899 UGG codons in E. coli was reported in 2015 by Budisa and Söll. Moreover, many biological phenomena, such as protein folding and stability, are based on synergistic effects at many positions in the protein sequence. In this context, the SPI method generates recombinant protein variants or alloproteins directly by substitution of natural amino acids with unnatural counterparts. An amino acid auxotrophic expression host is supplemented with an amino acid analog during target protein expression. This approach avoids the pitfalls of suppression-based methods and it is superior to it in terms of efficiency, reproducibility and an extremely simple experimental setup. Numerous studies demonstrated how global substitution of canonical amino acids with various isosteric analogs caused minimal structural perturbations but dramatic changes in thermodynamic, folding, aggregation spectral properties and enzymatic activity.
, the surface behaves elastically during contact. In both the Greenwood-Williamson and Mikic models the load is assumed to be proportional to the deformed area. Hence, whether the system behaves plastically or elastically is independent of the applied normal force.
== Mission objectives == Mission goal: Greater than 1 day in orbit Flight duration objective: 22 orbits resulting in a ~34 hour mission Capsule mass: 3,000 pounds (1,400 kg). The heaviest Mercury capsule due to enhancements to support longer flight mission duration
Sources: en.wikipedia.org
=== Pharmacodynamics === Benorterone is an antiandrogen, or an antagonist of the androgen receptor (AR), the biological target of the androgen sex hormones testosterone and dihydrotestosterone. In one study, the affinity of benorterone for the AR was found to be about 5-fold greater than that of cyproterone acetate in rat prostate cytosol; the Ki values were 0.7 nM for benorterone and 3.7 nM for cyproterone acetate, which were 243% and 46% of those of testosterone (Ki = 1.7 nM), respectively. However, another study found that benorterone had only 11% of the affinity of dihydrotestosterone for the androgen receptor. Although an antiandrogen, benorterone actually is a very weak partial agonist of the AR and has been reported to possess weak androgenic activity. The same is true for cyproterone acetate and other steroidal antiandrogens. Unlike certain other steroidal antiandrogens such as cyproterone acetate, benorterone is not also a progestogen, instead being described as a selective and pure AR antagonist similarly to nonsteroidal antiandrogens such as flutamide and bicalutamide. However, although it is described as not being a progestogen, benorterone was found to produce "a highly variable decrease in plasma testosterone levels," indicating that it has weak antigonadotropic effects. The reasons for this are unclear, as other pure antiandrogens such as cyproterone (not cyproterone acetate) and flutamide do not do this and instead produce consistent increases in testosterone levels.
On 17 July 2007, following a four-year inquiry, the House of Commons Select Committee on Standards and Privileges published its sixth report. The Parliamentary Commissioner for Standards, in an addendum to the report, concluded that there was no evidence that Galloway gained any personal benefit from either the former Iraqi administration, or from the Oil-for-Food Programme, but admitted that some documents had been unavailable to him. However, the Committee concluded, in the main body of the report:
They are cigar-shaped but slightly broader at the "front" end, which is the aboral, vegetal-pole end and eventually attaches to a substrate if the species has a polyp stage. Anthozoan larvae either have large yolks or are capable of feeding on plankton, and some already have endosymbiotic algae that help to feed them. Since the parents are immobile, these feeding capabilities extend the larvae's range and avoid overcrowding of sites. Scyphozoan and hydrozoan larvae have little yolk and most lack endosymbiotic algae, and therefore have to settle quickly and metamorphose into polyps. Instead, these species rely on their medusae to extend their ranges.
The advance voting on 1 February saw many complaints of issues with the election process. One reported issue, which was also seen in the previous election, was that election officials wrote wrong codes on ballot envelopes, raising concerns that the ballots might end up in a different district and therefore be counted for the wrong candidate. Voters also reported missing or incorrect on information boards at some polling stations. This included cases where a candidate's information was entirely missing from the information board. In some of these cases, it was reported that polling station officials initially claimed that the missing candidates had been disqualified and only later rectified the mistake. Those affected included candidates from the People's Party, Pheu Thai Party, and Democrat Party.
Sources: en.wikipedia.org
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.
DAC stands for drug affinity complex, a term describing the maleimidopropionic acid linker. This group forms a covalent bond with the cysteine residue on serum albumin after administration. The resulting adduct is what extends the circulating half life from minutes to days.
No. It is entirely synthetic and does not correspond to any known endogenous peptide. The design starts from human growth hormone releasing hormone and introduces deliberate substitutions. Any biological effect comes from mimicking the natural hormone at its receptor.
It binds the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Receptor activation raises cyclic AMP and promotes release of stored growth hormone granules. Because the peptide persists longer than natural releasing hormone, stimulation is prolonged rather than brief.