The short version of drug affinity complex fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-05-16. Anything still debated is marked as such rather than presented as settled.
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.
Pharmacokinetic behaviour differs sharply between the two forms. The DAC-bearing peptide shows an extended circulation time measured in days, whereas the version without the complex is cleared within roughly half an hour. This gap shapes how researchers design dosing schedules in animal models. Whether the prolonged presence of the DAC form produces effects meaningfully different from the short-acting variant remains an open question, since comparative human data are scarce.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight (with DAC) | ~3647 Da | Calculated from the full amino acid sequence |
| Molecular weight (without DAC) | ~3368 Da | Mod GRF(1-29) variant |
| Appearance | White lyophilized powder | Typical form supplied for research |
| Solubility | Soluble in water | Dissolves in aqueous buffers |
| Receptor target | GHRH receptor | Expressed on pituitary somatotroph cells |
=== Chemical === The chemistry of mendelevium is known largely in solution (as available quantities do not allow the creation of pure compounds), in which it can take on the +3 or +2 oxidation states. The +1 state has also been reported, but has not yet been confirmed. Before mendelevium's discovery, Seaborg and Katz predicted that it should be predominantly trivalent in aqueous solution and hence should behave similarly to other tripositive lanthanides and actinides. After the synthesis of mendelevium in 1955, these predictions were confirmed, first in the observation at its discovery that it eluted just after fermium in the trivalent actinide elution sequence from a cation-exchange column of resin, and later the 1967 observation that mendelevium could form insoluble hydroxides and fluorides that coprecipitated with trivalent lanthanide salts. Cation-exchange and solvent extraction studies led to the conclusion that mendelevium was a trivalent actinide with an ionic radius somewhat smaller than that of the previous actinide, fermium. Mendelevium can form coordination complexes with 1,2-cyclohexanedinitrilotetraacetic acid (DCTA). In reducing conditions, mendelevium(III) can be easily reduced to mendelevium(II), which is stable in aqueous solution. The standard reduction potential of the E°(Md3+→Md2+) couple was variously estimated in 1967 as −0.10 V or −0.20 V: later 2013 experiments established the value as −0.16±0.05 V. In comparison, E°(Md3+→Md0) should be around −1.74 V, and E°(Md2+→Md0) should be around −2.5 V.
== Medicine and biotechnology == Aminopeptidase has been studied for use in treating hypertension, inflammation, and some cancers. Aminopeptidase A (APA) is implicated in blood pressure regulation by converting angiotensin II to angiotensin III. APA inhibitors are being explored as potential antihypertensive agents, offering a novel approach to managing hypertension. Aminopeptidase N (APN) has been associated with the pathogenesis of inflammatory diseases such as rheumatoid arthritis and inflammatory bowel disease. Inhibitors of APN have demonstrated anti-inflammatory effects in animal models, positioning them as potential therapeutic agents for these conditions. Several aminopeptidases, including APN, APA, and leucine aminopeptidase (LAP), are overexpressed in various cancers. Their involvement in tumor growth, invasion, and angiogenesis makes them attractive targets for cancer therapy. Aminopeptidase inhibitors have shown promise in preclinical studies as potential anticancer agents.
For reasons of space, the periodic table is commonly presented with the f-block elements cut out and positioned as a distinct part below the main body. This reduces the number of element columns from 32 to 18. Both forms represent the same periodic table. The form with the f-block included in the main body is sometimes called the 32-column or long form; the form with the f-block cut out the 18-column or medium-long form. The 32-column form has the advantage of showing all elements in their correct sequence, but it has the disadvantage of requiring more space. The form chosen is an editorial choice, and does not imply any change of scientific claim or statement. For example, when discussing the composition of group 3, the options can be shown equally (unprejudiced) in both forms. Periodic tables usually at least show the elements' symbols; many also provide supplementary information about the elements, either via colour-coding or as data in the cells. Tables may include extra information such as the names and atomic numbers of the elements, their blocks, natural occurrences, standard atomic weight, states of matter, melting and boiling points, densities, as well as provide different classifications of the elements.
Sources: en.wikipedia.org
During the period he was Labour MP for Glasgow Kelvin, from 1997 to 2003, he voted against the whip 32 times, five votes out of 665 (0.8%) in the 1997–2001 parliament and the majority (27 votes out of 209 or 12.9%) in the period from the 2001 election until his expulsion from the Labour Party. He was one of several politicians arrested in February 2001 during a protest at the Faslane nuclear base in Scotland, which led to him being convicted of a breach of the peace and fined £180. In May 2002, he was among the 72 MPs who signed The Guardian's campaign to repeal the Act of Settlement 1701, alongside the Archbishop of York David Hope and several non-Anglican religious leaders.
== Classification == Cnidarians were for a long time grouped with ctenophores in the phylum Coelenterata, but increasing awareness of their differences caused them to be placed in separate phyla. Modern cnidarians are generally classified into four main classes: sessile Anthozoa (sea anemones, corals, sea pens); swimming Scyphozoa (jellyfish) and Cubozoa (box jellies); and Hydrozoa, a diverse group that includes all the freshwater cnidarians as well as many marine forms, and has both sessile members such as Hydra and colonial swimmers such as the Portuguese Man o' War. Staurozoa have recently been recognised as a class in their own right rather than a sub-group of Scyphozoa, and the parasitic Myxozoa and Polypodiozoa are now recognized as highly derived cnidarians rather than more closely related to the bilaterians.
The game won several publication awards, as well as "Computer Action Game of the Year" from the Academy of Interactive Arts & Sciences during the 3rd Annual Interactive Achievement Awards. The editors of PC Gamer US presented Opposing Force with their 1999 "Best Expansion Pack" award, and nominated it as 1999's overall best game of the year, although it lost the latter prize to Homeworld. They wrote that Opposing Force "makes history by becoming the first expansion pack to be considered for Game of the Year. Yes, it really is that good."
One of the first examples of this type of measurement has been clumped isotopes of methane.(See section of "natural gas" in Fossil fuels) Another strength of this kind of instruments is the ability to do site-specific isotopic ratio measurements. This technique is based on measuring DHRs of fragments from the ion source (e.g. CH3CH+2 of propane molecule) that samples hydrogen atoms from different parts of the molecule. In summary, direct molecular mass-spectrometry has been commonly used to measure laboratory spiked isotope tracers. Recently advanced high resolution gas source isotope ratio mass spectrometers can measure hydrogen isotopes of organic molecules directly. These mass spectrometers can provide high precision and high sensitivity. The drawback of this type of instruments includes high cost, and standardization difficulty. Also, studying site-specific isotopes with mass spectrometry is less straightforward and needs more constraints than the SNIF-NMR method, and can only distinguish isotopologues but not isotopomers.
Sources: en.wikipedia.org
The synthetic peptide keeps the receptor-binding region of GHRH but carries substitutions that resist enzymatic cleavage. In the DAC version, an added group also anchors the molecule to albumin, extending its presence in the bloodstream.
The maleimide group forms a covalent link with albumin, an abundant blood protein. This attachment slows clearance, so a single administration persists much longer than the unmodified peptide. The feature is the main reason the two variants are handled differently in study design.
It is not an approved therapeutic product in major regulatory jurisdictions. It appears in research chemical catalogs and scientific literature rather than pharmacy shelves. Clinical development was limited and did not reach approval.
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.