If you have been reading about DAC and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-12-08. Numbers and descriptions here follow the published literature rather than marketing material.
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.
CJC-1295 is a synthetic peptide belonging to the growth hormone-releasing hormone analog family. It comprises twenty-nine amino acid residues derived from the N-terminal region of natural GHRH. The molecule incorporates several non-natural substitutions that increase resistance to enzymatic degradation. These modifications extend its activity compared with the native hormone fragment. Researchers use it to study pituitary growth hormone secretion in laboratory and clinical settings. This compound is distinct from native GHRH in its stability profile.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight (no linker) | ~3.37 kDa | Calculated from peptide sequence |
| Molecular weight (with linker) | ~3.65 kDa | Includes albumin-binding moiety |
| Appearance | White to off-white powder | Typically lyophilized |
| Solubility | Soluble in water | Also dissolves in aqueous buffers |
| Common synonyms | Modified GRF(1-29), DAC:GRF | Usage varies by source |
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.
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.
Two forms circulate under the CJC-1295 name, and they differ by a single appended group. The version without a drug affinity complex carries four substitutions along the peptide chain, including a D-alanine near the amino terminus and replacements at three other positions. These changes block the enzyme dipeptidyl peptidase IV and remove a methionine residue that is prone to oxidation. The modified fragment is frequently labeled MOD GRF 1-29. Naming conventions are inconsistent across informal sources, which is a common source of confusion.
The second form adds a maleimide-bearing linker to the lysine at the carboxyl end. This group reacts with cysteine-34 on circulating serum albumin, forming a covalent bond that keeps the peptide in the bloodstream for far longer. ConjuChem developed the molecule as a way to extend the action of a peptide without frequent administration. The albumin attachment is the defining structural feature of the drug affinity complex version. Whether continuous exposure produces effects distinct from shorter pulses remains an unresolved research question.
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.
== Side effects == Side effects of tavapadon may include nausea, headache, dizziness, fatigue or asthenia, dysgeusia, vomiting, dry mouth, and anxiety. Other potential but less common side effects include hypotension, orthostatic hypotension, impulsive control problems, compulsive behaviors, hallucinations, psychotic-like behaviors, and dyskinesia.
There are numerous methods employed for fiber-typing, and confusion between the methods is common among non-experts. Two commonly confused methods are histochemical staining for myosin ATPase activity and immunohistochemical staining for myosin heavy chain (MHC) type. Myosin ATPase activity is commonly—and correctly—referred to as simply "fiber type", and results from the direct assaying of ATPase activity under various conditions (e.g. pH). Myosin heavy chain staining is most accurately referred to as "MHC fiber type", e.g. "MHC IIa fibers", and results from determination of different MHC isoforms. These methods are closely related physiologically, as the MHC type is the primary determinant of ATPase activity. However, neither of these typing methods is directly metabolic in nature; they do not directly address oxidative or glycolytic capacity of the fiber. When "type I" or "type II" fibers are referred to generically, this most accurately refers to the sum of numerical fiber types (I vs. II) as assessed by myosin ATPase activity staining (e.g. "type II" fibers refers to type IIA + type IIAX + type IIXA ... etc.). Below is a table showing the relationship between these two methods, limited to fiber types found in humans. Subtype capitalization is used in fiber typing vs. MHC typing, and some ATPase types actually contain multiple MHC types. Also, a subtype B or b is not expressed in humans by either method. Early researchers believed humans to express a MHC IIb, which led to the ATPase classification of IIB.
=== Death === Kratom overdose is a subject of concern in many countries because of the associated rising number of hospitalizations and deaths in which chronic kratom use is a contributing factor. According to clinical reviews, a kratom overdose can cause liver toxicity, seizures, coma, and death, especially in combination with excessive alcohol use. Between 2011 and 2017, 44 U.S. deaths were kratom-related. However, many cases could not be fully assessed, due to limited information. People who die from kratom use typically have taken it in combination with other substances, or have underlying health conditions. Over 18 months in 2016 and 2017, 152 overdose deaths involving kratom were reported in the United States, with kratom as the primary overdose agent in 91 of the deaths, and 7 with kratom being the only agent detected. Nine deaths occurred in Sweden during 2010–11 relating to use of Krypton, a mixture of kratom, caffeine and O-desmethyltramadol, a metabolite of the opioid analgesic tramadol. Between 2020 and 2024, the Centers for Disease Control and Prevention found that kratom was involved in over 5,200 fatal overdoses in the United States.
Sources: en.wikipedia.org
=== Applications === Libraries of peptide aptamers have been used as "mutagens", in studies in which an investigator introduces a library that expresses different peptide aptamers into a cell population, selects for a desired phenotype, and identifies those aptamers that cause the phenotype. The investigator then uses those aptamers as baits, for example in yeast two-hybrid screens to identify the cellular proteins targeted by those aptamers. Such experiments identify particular proteins bound by the aptamers, and protein interactions that the aptamers disrupt, to cause the phenotype. In addition, peptide aptamers derivatized with appropriate functional moieties can cause specific post-translational modification of their target proteins, or change the subcellular localization of the targets.
It is important to investigate the rate at which the solute is transferred between the two phases, in some cases by an alteration of the contact time it is possible to alter the selectivity of the extraction. For instance, the extraction of palladium or nickel can be very slow because the rate of ligand exchange at these metal centers is much lower than the rates for iron or silver complexes.
== ISO 4500 - ISO 4999 == ISO 4548 Methods of test for full-flow lubricating oil filters for internal combustion engines ISO 4548-7:2012 Part 7: Vibration fatigue test ISO 4551:1987 Ferroalloys – Sampling and sieve analysis ISO 4552 Ferroalloys – Sampling and sample preparation for chemical analysis ISO 4552-1:1987 Part 1: Ferrochromium, ferrosilicochromium, ferrosilicon, ferrosilicomanganese, ferromanganese ISO 4552-2:1987 Part 2: Ferrotitanium, ferromolybdenum, ferrotungsten, ferroniobium, ferrovanadium ISO 4570 Tyre valve threads ISO 4578 Adhesives — Determination of peel resistance of high-strength adhesive bonds — Floating-roller method ISO 4582 Plastics — Determination of changes in colour and variations in properties after exposure to daylight under glass, natural weathering or laboratory light sources ISO 4587 Adhesives — Determination of tensile lap-shear strength of rigid-to-rigid bonded assemblies ISO 4618:2014 Paints and varnishes – Terms and definitions ISO 4628 Paints and varnishes – Evaluation of degradation of coatings – Designation of quantity and size of defects, and of intensity of uniform changes in appearance ISO 4628-1 General introduction and designation system ISO 4628-2 Assessment of degree of blistering ISO 4628-3 Assessment of degree of rusting ISO 4628-4 Assessment of degree of cracking ISO 4628-5 Assessment of degree of flaking ISO 4628-6 Assessment of degree of chalking by tape method ISO 4628-7 Assessment of degree of chalking by velvet method ISO 4628-8 Assessment of degree of delamination and corrosion around a scribe ISO 4628-10 Assessment of degree of filiform corrosion ISO 4648:1991 Rubber, vulcanized or thermoplastic — Determination of dimensions of test pieces and products for test purposes [Withdrawn: replaced with ISO 23529] ISO 4661 Rubber, vulcanized — Preparation of samples and test pieces ISO 4661-1:1993 Rubber, vulcanized or thermoplastic — Preparation of samples and test pieces — Part 1: Physical tests [Withdrawn: replaced with ISO 23529] ISO 4661-2:2018 Rubber, vulcanized — Preparation of samples and test pieces — Part 2: Chemical tests ISO 4683 Raw sheep skins ISO 4683-1:1998 Part 1: Descriptions of defects ISO 4720:2009 Essential oils – Nomenclature ISO 4730:2017 Essential oil of Melaleuca, terpinen-4-ol type (Tea Tree oil) ISO 4786:1977 Enclosed-scale adjustable-range thermometers [Withdrawn without replacement] ISO 4787:2010 Laboratory glassware – Volumetric instruments – Methods for testing of capacity and for use ISO 4788:2005 Laboratory glassware – Graduated measuring cylinders ISO 4791 Laboratory apparatus – Vocabulary relating to apparatus made essentially from glass, porcelain or vitreous silica ISO 4791-1:1985 Part 1: Names for items of apparatus ISO 4795:1996 Glass for thermometer bulbs ISO 4801:1979 Glass alcoholometers and alcohol hydrometers not incorporating a thermometer ISO 4805:1982 Laboratory glassware – Thermo-alcoholometers and alcohol-thermohydrometers ISO 4824:1993 Dentistry — Ceramic denture teeth [Withdrawn: replaced with ISO 22112] ISO 4831:2006 Microbiology of food and animal feeding stuffs – Horizontal method for the detection and enumeration of coliforms – Most probable number technique ISO 4832:2006 Microbiology of food and animal feeding stuffs – Horizontal method for the enumeration of coliforms – Colony-count technique ISO 4833 Microbiology of the food chain – Horizontal method for the enumeration of microorganisms ISO 4833-1:2013 Part 1: Colony count at 30 degrees C by the pour plate technique ISO 4833-2:2013 Part 2: Colony count at 30 degrees C by the surface plating technique ISO 4848:1980 Concrete — Determination of air content of freshly mixed concrete — Pressure method [Withdrawn: replaced with ISO 1920-2] ISO 4858:1982 Wood — Determination of volumetric shrinkage [Withdrawn: replaced with ISO 13061-14] ISO 4859:1982 Wood — Determination of radial and tangential swelling [Withdrawn: replaced with ISO 13061-15] ISO 4860:1982 Wood — Determination of volumetric swelling [Withdrawn: replaced with ISO 13061-16] ISO 4866:2010 Mechanical vibration and shock – Vibration of fixed structures – Guidelines for the measurement of vibrations and evaluation of their effects on structures ISO 4871:1996 Acoustics – Declaration and verification of noise emission values of machinery and equipment ISO/IEC 4873:1991 Information technology – ISO 8-bit code for information interchange – Structure and rules for implementation ISO 4875 Metal-cutting band saw blades ISO 4875-1:2006 Part 1: Vocabulary ISO 4880:1997 Burning behaviour of textiles and textile products – Vocabulary ISO 4882:1979 Office machines and data processing equipment – Line spacings and character spacings ISO 4885:2017 Ferrous materials – Heat treatments – Vocabulary ISO 4892 Plastics – Methods of exposure to laboratory light sources ISO 4902:1989 Information technology – Data communication – 37-pole DTE/DCE interface connector and contact number assignments ISO 4903:1989 Information technology – Data communication – 15-pole DTE/DCE interface connector and contact number assignments ISO/IEC 4909:2006 Identification cards – Financial transaction cards – Magnetic stripe data content for track 3 ISO 4921:2000 Knitting – Basic concepts – Vocabulary ISO/IEC 4922-1 Information security — Secure multiparty computation ISO/IEC 4922-1:2023 Part 1: General ISO 4977 Double cold-reduced electrolytic tinplate ISO 4977-1:1984 Part 1: Sheet [Withdrawn: replaced with ISO 11949] ISO 4977-2:1984 Part 2: Coil for subsequent cutting into sheets [Withdrawn: replaced with ISO 11949]
Sources: en.wikipedia.org
No. It is a synthetic analogue modeled on the first 29 residues of human GHRH. The substitutions and any linker are laboratory modifications rather than features of the endogenous peptide.
Early development used the albumin-binding form, and a shorter variant was later discussed under the same label. Because the two differ in half-life and handling, ambiguity arises whenever a source omits the variant designation.
The compound derives from that fragment but is not identical to it. The parent fragment lacks the stabilizing substitutions, so its degradation rate and duration of action differ noticeably.
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.