This is a working overview of CJC-1295, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-16. Anything still debated is marked as such rather than presented as settled.
Both forms act at the pituitary receptor for growth hormone-releasing hormone and increase growth hormone output, which in turn raises insulin-like growth factor 1. A long-acting analog produces sustained rather than pulsatile stimulation, and the physiological consequences of that pattern are not fully settled. Published human data on the extended form remain limited, and much of what circulates in discussion traces to early company reports rather than independent replication. How sustained exposure affects normal feedback remains an open question.
The distinguishing feature of the DAC form is a maleimide-containing group that reacts with the free thiol of cysteine-34 on human serum albumin. This reaction forms a covalent bond without enzymatic assistance, and it takes place after the peptide enters the bloodstream. Because albumin is abundant and long-lived, the attached peptide is carried through circulation far longer than an unmodified fragment would survive. The chemistry is a deliberate pharmacokinetic strategy rather than a change to receptor activity.
Enzymatic protection is a separate mechanism from plasma protein binding. The four substitutions in the backbone reduce recognition by dipeptidyl peptidase IV, which normally cleaves the natural hormone within minutes. Without the reactive group, this resistance still yields only a short window of activity, generally reported in the range of tens of minutes. With it, reported half-lives in early human work extended to several days. The size of that gap is the main practical distinction between the two materials.
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.
Binding of the peptide to the growth hormone-releasing hormone receptor on pituitary somatotrophs triggers a G protein coupled cascade that raises cyclic AMP and opens calcium channels. The result is greater secretion of growth hormone into the bloodstream. Because the peptide acts at the same receptor as the natural hypothalamic hormone, its effect is amplified pulse size rather than an entirely separate release pathway. Receptor binding alone does not determine the response, since somatostatin tone and other inputs modulate the final output.
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.
| Property | Value | Notes |
|---|---|---|
| Duration with linker | Several days | Reported in early human work |
| Duration without linker | Tens of minutes | Short plasma residence |
| Albumin attachment site | Cysteine-34 | Covalent maleimide reaction |
| Primary receptor | Pituitary GHRH receptor | Stimulates growth hormone release |
| Downstream marker | Insulin-like growth factor 1 | Indirect measure of activity |
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.
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.
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.
The attached maleimide group explains the unusual duration of the DAC version. After injection it reacts with the thiol of cysteine-34 on serum albumin, forming a stable covalent bond. The resulting conjugate is too large for rapid kidney filtration and is shielded from many peptidases. Reported half-lives for this form reach several days, whereas the version without the group is cleared in roughly half an hour. That gap is the main pharmacological difference between the two.
Clearance profiles diverge sharply between the two versions. The albumin-binding molecule stays in plasma for several days, whereas the unmodified analog is largely gone within about half an hour in reported work. Cleavage by dipeptidyl peptidase IV is a major contributor to the short life of the unmodified sequence. These gaps mean the two versions cannot be substituted for each other in study design or in reading results side by side.
Reports on this compound commonly follow serum growth hormone and insulin-like growth factor 1 across defined time windows. Protocols differ in sampling frequency, assay platform, and participant characteristics, which makes direct comparison between publications difficult. Some work focuses on pulsatile release patterns instead of average concentrations. Whether repeated exposure alters endogenous hormone rhythms over long periods remains an open question, and the formal literature is thinner than the volume of informal commentary implies.
Once in circulation, the peptide binds the growth hormone-releasing hormone receptor displayed on pituitary somatotroph cells. Receptor activation couples to Gs proteins, elevates intracellular cyclic AMP, and drives protein kinase A signaling inside the cell. That cascade increases discharge of growth hormone into the bloodstream. The analog therefore operates through a receptor pathway that already exists for the body's own releasing hormone, rather than through an engineered artificial target.
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.
Two related forms circulate in technical discussion under the same family name. The original version carries a drug affinity complex (DAC) that binds covalently to serum albumin after administration, and this linkage substantially extends circulation time. A second form, frequently written as modified GRF(1-29) or CJC-1295 without DAC, lacks that linker and clears much faster. The naming is a frequent source of confusion because the shorthand CJC-1295 can refer to either form depending on the source. Reports sometimes fail to specify which variant was studied.
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.
== Significance == The transmembrane region of many integral membrane proteins consists of one or more alpha helices. The orientations and interactions of these helices directly affect cell signaling and molecular transport across the bilayer. The hydrophobic environment of the phospholipid tails in turn modulates the position and structure of such domains and thus may influence protein function. Conversely, the bilayer itself can (locally) change the thickness of its hydrocarbon region to interact optimally with hydrophobic regions of a transmembrane protein (a.k.a. hydrophobic matching). WALPs provide an effective model for studying such interactions because of their systematic design of a core of hydrophobic, alternating alanine and leucine regions. This core is readily manipulated by extending or decreasing the number of amino acids. Another key feature is the presence of "anchoring" residues at the ends of the helix, which are tryptophan residues in the WALP versions. Substituting the anchoring tryptophan residues for charged residues, such as lysine, yields "KALP" peptides. This class of model peptides has proved useful for studying the impact of changes in lipid composition on peptide insertion. Following detailed experimental studies by various techniques, the WALP and related peptides have become commonly used model systems in computational biology.
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Signs of sickle cell disease usually begin in early childhood. The severity of symptoms can vary from person to person, as can the frequency of crisis events. Sickle cell disease may lead to various acute and chronic complications, several of which have a high mortality rate.
Probing protein structure and function: By using amino acids with slightly different size such as O-methyltyrosine or dansyl alanine instead of tyrosine, and by inserting genetically coded reporter moieties (color-changing and/or spin-active) into selected protein sites, chemical information about the protein's structure and function can be measured. Probing the role of post-translational modifications in protein structure and function: By using amino acids that mimic post-translational modifications such as phosphoserine, biologically active protein can be obtained, and the site-specific nature of the amino acid incorporation can lead to information on how the position, density, and distribution of protein phosphorylation effect protein function. Identifying and regulating protein activity: By using photocaged aminoacids, protein function can be "switched" on or off by illuminating the organism. Changing the mode of action of a protein: One can start with the gene for a protein that binds a certain sequence of DNA and, by inserting a chemically active amino acid into the binding site, convert it to a protein that cuts the DNA rather than binding it. Improving immunogenicity and overcoming self-tolerance: By replacing strategically chosen tyrosines with p-nitro phenylalanine, a tolerated self-protein can be made immunogenic. Selective destruction of selected cellular components: using an expanded genetic code, unnatural, destructive chemical moieties (sometimes called "chemical warheads") can be incorporated into proteins that target specific cellular components.
1985–1987 – 1.3 L (1,296 cc) E3, 2 barrel, 8-valve, 74 PS (54 kW; 73 hp) Gross / 10.5 kg⋅m (103 N⋅m; 76 lb⋅ft) 1987–1989 – 1.3 L (1,323 cc) B3, 2 barrel, 8-valve, 67 PS (49 kW; 66 hp) Net / 10.4 kg⋅m (102 N⋅m; 75 lb⋅ft) 1985–1987 – 1.5 L (1,490 cc) E5, 2 barrel carburettor, 8-valve, 85 PS (63 kW; 84 hp) Gross / 12.3 kg⋅m (121 N⋅m; 89 lb⋅ft) Gross – Net rating 70 PS (51 kW; 69 hp) / 11.2 kg⋅m (110 N⋅m; 81 lb⋅ft) 1985–1987 – 1.5 L (1,490 cc) E5, EGi, 8-valve, 95 PS (70 kW; 94 hp) Gross/12.6 kg⋅m (124 N⋅m; 91 lb⋅ft) Gross – Net rating 76 PS (56 kW; 75 hp) / 11.6 kg⋅m (114 N⋅m; 84 lb⋅ft) 1985–1987 – 1.5 L (1,490 cc) E5T, turbo EGi, 8-valve, 115 PS (85 kW; 113 hp) Gross / 16.5 kg⋅m (162 N⋅m; 119 lb⋅ft) 1987–1989 – 1.5 L (1,498 cc) B5, 2 barrel, 12-valve, 76 PS (56 kW; 75 hp) Net / 11.4 kg⋅m (112 N⋅m; 82 lb⋅ft) 1987–1989 – 1.6 L (1,597 cc) B6, EGi, 8-valve, 85 PS (63 kW; 84 hp) Net / 12.5 kg⋅m (123 N⋅m; 90 lb⋅ft) 1986–1989 – 1.6 L (1,597 cc) B6D, EGi, 16-valve, 110 PS (81 kW; 108 hp) Net / 13.5 kg⋅m (132 N⋅m; 98 lb⋅ft) 1985–1989 – 1.6 L (1,597 cc) B6T, turbo EGi, 16-valve, 140 PS (103 kW; 138 hp) Net / 19.0 kg⋅m (186 N⋅m; 137 lb⋅ft) 1985–1989 – 1.7 L (1,720 cc) PN, diesel, 8-valve, 59 PS (43 kW; 58 hp) Gross / 10.8 kg⋅m (106 N⋅m; 78 lb⋅ft) Gross – Net rating 55 PS (40 kW; 54 hp) / 10.2 kg⋅m (100 N⋅m; 74 lb⋅ft), 1987–1989; Net rating: 58 PS (43 kW; 57 hp) / 10.7 kg⋅m (105 N⋅m; 77 lb⋅ft)
Sources: en.wikipedia.org
The two substrates of this enzyme are precorrin-2 and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are sirohydrochlorin, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is precorrin-2:NAD+ oxidoreductase. Other names in common use include Met8p, SirC, and CysG. This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B12) in anaerobic bacteria and to Cofactor F430.
=== COVID-19 pandemic === Bukele issued an executive decree on 11 March 2020 imposing a "quarantine throughout the national territory" ("cuarentena en todo el territorio nacional"), shortly after World Health Organization (WHO) director-general Tedros Adhanom Ghebreyesus declared the COVID-19 outbreak a pandemic. The quarantine suspended all school activities for 21 days, prohibited foreigners from entering the country, and mandated a 30-day quarantine for everyone entering the country. Bukele confirmed the first case of COVID-19 in El Salvador on 18 March 2020. The country's first death from the disease was recorded on 31 March. On 5 May 2023, the Pan American Health Organization declared the end of the pandemic. According to the WHO, As of 27 September 2023, El Salvador had 201,807 confirmed cases of COVID-19 and 4,230 deaths from the disease by 2 June 2023; the WHO reported that 11,426,688 doses of the COVID-19 vaccine had been administered in El Salvador by that date.
Computer Games Magazine argued the futility of reviewing the game due to its episodic nature; as the first part of a three-part story arc, it is difficult to judge it when divorced from the final product. Game Revolution expressed disappointment at a lack of new features such as environments and weapons. During the 10th Annual Interactive Achievement Awards, the Academy of Interactive Arts & Sciences nominated Half-Life 2: Episode One for "First-Person Action Game of the Year".
A somatomammotroph or somatomammotrophic cell, also known as a somatolactotroph or somatolactotrophic cell, is a type of cell of the anterior pituitary gland that produces both somatotropin (growth hormone) and prolactin. Cells that secrete only somatotropin or only prolactin are known as somatotrophs and mammotrophs, respectively.
Sources: en.wikipedia.org
== Functions and requirement == The Food and Nutrition Board (FNB) of the U.S. Institute of Medicine has set Recommended Dietary Allowances (RDAs) for essential amino acids in 2002. For adults 19 years and older, 19 mg of isoleucine/kg body weight is required daily. Beside its biological role as a nutrient, isoleucine also participates in regulation of glucose metabolism. Isoleucine is an essential component of many proteins. As an essential amino acid, isoleucine must be ingested or protein production in the cell will be disrupted. Fetal hemoglobin is one of the many proteins that require isoleucine. Isoleucine is present in the gamma chain of fetal hemoglobin and must be present for the protein to form. Genetic diseases can change the consumption requirements of isoleucine. Amino acids cannot be stored in the body. Buildup of excess amino acids will cause a buildup of toxic molecules so, humans have many pathways to degrade each amino acid when the need for protein synthesis has been met. Mutations in isoleucine-degrading enzymes can lead to dangerous buildup of isoleucine and its toxic derivative. One example is maple syrup urine disease (MSUD), a disorder that leaves people unable to breakdown isoleucine, valine, and leucine. People with MSUD manage their disease by a reduced intake of all three of those amino acids alongside drugs that help excrete built-up toxins. Many animals and plants are dietary sources of isoleucine as a component of proteins. Foods that have high amounts of isoleucine include eggs, soy protein, seaweed, turkey, chicken, lamb, cheese, and fish.
Most bacterial species are either spherical, called cocci (singular coccus, from Greek kókkos, grain, seed), or rod-shaped, called bacilli (sing. bacillus, from Latin baculus, stick). Some bacteria, called vibrio, are shaped like slightly curved rods or comma-shaped; others can be spiral-shaped, called spirilla, or tightly coiled, called spirochaetes. A small number of other unusual shapes have been described, such as star-shaped bacteria. This wide variety of shapes is determined by the bacterial cell wall and cytoskeleton and is important because it can influence the ability of bacteria to acquire nutrients, attach to surfaces, swim through liquids and escape predators.
This way, such adjustments can be used to release the proteins of interest. Additionally, concentration of counterions can be gradually varied to affect the retention of the ionized molecules, thus separate them. This type of elution is called gradient elution. On the other hand, step elution can be used, in which the concentration of counterions are varied in steps. This type of chromatography is further subdivided into cation exchange chromatography and anion-exchange chromatography. Positively charged molecules bind to cation exchange resins, while negatively charged molecules bind to anion exchange resins. The ionic compound consisting of the cationic species M+ and the anionic species B− can be retained by the stationary phase. Cation exchange chromatography retains positively charged cations because the stationary phase displays a negatively charged functional group:
Sources: en.wikipedia.org
A maleimide moiety reacts with the thiol of cysteine-34, forming a covalent bond. The reaction occurs in circulation without enzymatic catalysis.
The group is intended to alter distribution and persistence, not receptor engagement. The peptide portion still binds the pituitary receptor, so the primary difference is duration rather than potency.
Not firmly. Early reports describe several days for the extended form, but independent confirmations are sparse, and values vary with assay method and study design.
Reported values cluster in the range of several days, reflecting slow release from the albumin complex. Estimates differ across species and assay platforms. The figure describes circulation time in study settings rather than a fixed property.