This is a working overview of DAC, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-08. Anything still debated is marked as such rather than presented as settled.
Two principal forms appear in the literature and in research supply. One carries a drug affinity complex, a maleimide-based group that forms a covalent bond with circulating albumin. This linkage slows clearance and produces a long-lasting elevation of peptide levels. The other form lacks that group and is often labeled MOD GRF(1-29). It has a much shorter circulation time. Both variants retain the same core receptor-binding sequence. Reported half-lives differ substantially between the two.
At the pituitary, the peptide binds the growth hormone-releasing hormone receptor on somatotroph cells. Receptor activation raises intracellular cyclic AMP and triggers release of stored growth hormone. Somatostatin and other hypothalamic signals modulate this response. Negative feedback from insulin-like growth factor 1 also influences output. The same regulatory architecture operates with the native hormone. Whether the synthetic analog alters feedback dynamics over repeated exposure remains an open question. Most published receptor work uses cell models rather than intact human systems.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight, DAC form | About 3647 Da | Varies with salt form |
| Molecular weight, non-DAC form | About 3358 Da | MOD GRF(1-29) |
| Solubility class | Water soluble | Also dissolves in polar solvents |
| Reported half-life, DAC form | About five to eight days | Values from human studies |
| Common synonyms | CJC-1295; MOD GRF(1-29) | Name depends on variant |
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.
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.
=== Pharmacodynamics === Compared to concentration dependent bactericidal antibiotics like aminoglycosides and fluoroquinolones, the antibacterial activity of β-lactam antibiotics are generally more time dependent. Unlike the former, when piperacillin-tazobactam concentrations exceed minimum inhibitory concentrations (MIC) of a pathogen by five folds, the exponential relationship between concentration and activity begins to level off. Otherwise, piperacillin-tazobactam bactericidal efficacy is shown to consist of a strong association with the duration of time the concentration exceeds minimum inhibitory concentrations (T>MIC). When the T>MIC in the serum equates to 60–70% of the frequency for drug administration (dosing interval), maximal activity is achieved against Gram-negative bacteria, while for Gram-positive bacteria it occurs at around 40–50%. Within a 24-hour period in one clinical study, a T>MIC surpassing 60% was found for piperacillin-susceptible bacteria including Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus in two dosing regimes (4.5 g every 8 hours and 3.375 g every 8 hours). The evidence for this was obtained through Monte Carlo experiments procured by a special program (OPTAMA), where for several different scenarios (e.g. hospital acquired infections, secondary peritonitis, skin or soft tissue infections), the probability of attaining those figures were in the ranges of 85–95% and 90–89% respectively for the two regimes.
== Performing with the Grateful Dead == In early 1970, Lagin initiated a correspondence with Jerry Garcia after seeing the Grateful Dead at the Boston Tea Party in 1969. In May 1970, he helped facilitate a concert and free live outdoor performance featuring the band at MIT that coincided with the Kent State shootings. That summer, Lagin, at Garcia's invitation, visited San Francisco and contributed piano to "Candyman" during the American Beauty album sessions, played in several jams, and started what would become close friendships with Garcia, bassist Phil Lesh, and David Crosby. From 1970 to 1975, Lagin contributed Hammond B3 organ, electric piano, and clavichord to material of his choice (primarily—but not exclusively—songs with long instrumental passages) at several Grateful Dead concerts. His first performances with the Grateful Dead were on November 5 and November 8, 1970 at the Capitol Theater in Port Chester, New York; his first complete concert was at Boston University's Sargent Gym on November 21, 1970. During many 1974 Grateful Dead concerts over several tours, including Europe, he performed a middle set of electronic music, including parts of his composition Seastones, on computer-controlled analog synthesizers with Phil Lesh on electronically processed bass. Some sets included Jerry Garcia playing guitar filtered through effects processors and Bill Kreutzmann on drums; these sets occasionally segued into the final Grateful Dead set, with Lagin performing with the Dead, including an appearance in The Grateful Dead Movie.
== Early life == Geneviève Meurgues was born on 4 February 1931 in Paris, into a family originally from Saint-Germain-de-Modéon. She had sister and brother, Christiane and Bernard. Until 1962, she worked in a medical analysis laboratory while completing her education in chemistry and biochemistry at the Conservatoire national des arts et métiers. She graduated as a chemical engineer in 1967, writing her thesis on the nucleic acids of the fungus Aspergillus niger.
White was married to his wife Edna for more than 40 years. He died unexpectedly on February 14, 1980, in Santa Barbara, California, where he had gone that day from his home in Palo Alto to deliver a lecture at the University of California. Several awards in the field of biochemistry have been named for White, including at Oakland University in Michigan, Wayne State University, George Washington University School of Medicine and the Gladstone Institutes. 1935 – Traveling Fellowship, American Physiological Society, for the XVth International Congress of Physiology (Leningrad and Moscow) 1938 – Eli Lilly Prize in Biochemistry 1960 – Distinguished Alumni Award, University of Denver 1967 – Sesquicentennial Alumni Award, University of Michigan 1969 – Borden Award, Association of American Medical Colleges 1959 – Doctor of Humane Letters, Yeshiva University 1975 – Doctor of Science, University of Denver
Abbreviations for predicted unobserved decay: α for alpha decay, B for beta decay, 2B for double beta decay, E for electron capture, 2E for double electron capture, IT for isomeric transition, SF for spontaneous fission, * for the nuclides whose half-lives have lower bound. Predicted double beta decay has only been listed when beta decay is not also possible. (This does not apply to zirconium-96, which has been observed to decay both ways.) ^ Tantalum-180m is a "metastable isotope", meaning it is an excited nuclear isomer of tantalum-180. See isotopes of tantalum. However, the half-life of this nuclear isomer is so long that it has never been observed to decay, and it thus is an "observationally stable" primordial nuclide, a rare isotope of tantalum. This is the only nuclear isomer with a half-life so long that it has never been observed to decay. It is thus included in this list. ^^ Bismuth-209 was long believed to be stable, due to its half-life of 2.01×1019 years, which is more than a billion times the age of the universe. § Europium-151 and samarium-147 are primordial nuclides with very long half-lives of 4.62×1018 years and 1.066×1011 years, respectively.
Sources: en.wikipedia.org
=== 2026 Iran war === Following the assassination of Ali Khamenei during the 2026 Iran war, Badr Organization leader Hadi al-Amiri pledged allegiance to the new supreme leader of Iran, Mojtaba Khamenei.
=== Health === According to the House of Commons survey of female genital mutilation, in the year to 31 March 2016, Brent represented the highest number of attendees, by current residence or visiting location, to medical services, at 1,250, 545 more than the next-highest local authority, Bristol. In 2015, the BBC reported that some wards of Brent and four other London boroughs had rates of tuberculosis over ten times the national average, and higher than rates seen in Iraq and Rwanda.
=== Tumor suppression === Peppermint has been found to promote anti-tumor activity in laboratory studies by suppressing okadaic acid (OA), a tumor-promoting toxin. It is one of eight plants shown to significantly reduce the effects of OA. Menthol, the naturally occurring compound found in mint plants, appears to suppress arylamine N-acetyltransferase (NAT) activity in liver tumor cells. NAT activity plays a critical role in tumor survival, growth, and chemotherapy resistance. Peppermint extract has been shown to exert a toxic effect on cancer cells by increasing the activity of the cell-protecting antioxidant enzymes superoxide dismutase and glutathione peroxidase.
Aggregated proteins are associated with prion-related illnesses such as Creutzfeldt–Jakob disease, bovine spongiform encephalopathy (mad cow disease), amyloid-related illnesses such as Alzheimer's disease and familial amyloid cardiomyopathy or polyneuropathy, as well as intracellular aggregation diseases such as Huntington's and Parkinson's disease. These age onset degenerative diseases are associated with the aggregation of misfolded proteins into insoluble, extracellular aggregates and/or intracellular inclusions including cross-β amyloid fibrils. It is not completely clear whether the aggregates are the cause or merely a reflection of the loss of protein homeostasis, the balance between synthesis, folding, aggregation and protein turnover. Recently the European Medicines Agency approved the use of Tafamidis or Vyndaqel (a kinetic stabilizer of tetrameric transthyretin) for the treatment of transthyretin amyloid diseases. This suggests that the process of amyloid fibril formation (and not the fibrils themselves) causes the degeneration of post-mitotic tissue in human amyloid diseases. Misfolding and excessive degradation instead of folding and function leads to a number of proteinopathies, diseases such as antitrypsin-associated emphysema, cystic fibrosis and the lysosomal storage diseases, where loss of function is the origin of the disorder. While protein replacement therapy has historically been used to correct the latter disorders, an emerging approach is to use pharmaceutical chaperones to fold mutated proteins to render them functional.
Sources: en.wikipedia.org
=== Pneumonia === The piperacillin-tazobactam (piptaz) antibiotic commonly used with an aminoglycoside retains similar levels of drug safety and efficacy as other antibiotic combinations such as ceftazidime with the aminoglycoside tobramycin in the treatment of patients with hospital acquired pneumonia. In a clinical comparison primarily targeting patients not initially placed in intensive care units, piperacillin-tazobactam was found to produce higher clinical and microbiological rates of success. By contrast, the drug efficacy of ceftazidime and piperacillin-tazobactam resulted in similar response rates (61.5% and 63.9 respectively) when tobramycin was added into both groups. Identical evaluations are shown when compared to the imipenem and tobramycin combination, where the administration of piperacillin-tazobactam on patients (especially those under mechanical ventilation) was only consisted of a slightly higher response rate.
, the plot would show a negative spike as temperature increases beyond the melting point, since melting is an endothermic process. Conversely, it would show a positive spike as temperature drops below the melting point. This curve can be used to calculate enthalpies of transitions. This is done by taking the time-integral of peak corresponding to a given transition:
=== Hospital acute care === Bridion (sugammadex) ($1.7 billion in 2024 revenues) is a medication for the reversal of neuromuscular blockade induced by rocuronium and vecuronium in general anaesthesia. Prevymis (letermovir) ($0.8 billion in 2024 revenues) is used for the prevention of cytomegalovirus infections. Dificid (fidaxomicin) ($0.3 billion in 2024 revenues) is a tiacumicin. Zerbaxa (ceftolozane/tazobactam ($0.3 billion in 2024 revenues) is an antibiotic used to treat urinary tract infections. Noxafil (posaconazole) ($0.2 billion in 2024 revenues) is a triazole antifungal.
Sources: en.wikipedia.org
It is a synthetic peptide modeled on growth hormone-releasing hormone. The molecule is used in research on pituitary growth hormone secretion. It differs from the natural hormone through several stabilizing substitutions.
The DAC form carries a maleimide group that binds albumin and extends circulation time. The non-DAC form lacks this group and clears much faster. Both share the same receptor-binding core.
It targets the growth hormone-releasing hormone receptor on pituitary somatotroph cells. Activation raises cyclic AMP and promotes growth hormone release. Normal feedback pathways remain part of the response.
It acts on the growth hormone-releasing hormone receptor found on pituitary somatotroph cells. Activation of that receptor triggers growth hormone release through a cyclic AMP dependent pathway.