Maleimide chemistry is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-07-28. Numbers and descriptions here follow the published literature rather than marketing material.
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 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.
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.
| 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 |
Naming in this area is inconsistent, and readers should treat product labels with care. In much of the literature and in vendor catalogs, the unqualified term refers to the albumin-binding version, while the version lacking the DAC group appears as modified GRF(1-29), mod GRF(1-29), or the same name with a without-DAC qualifier. Because one abbreviation has been applied to both materials, the only reliable way to identify a sample is to check the stated sequence and the presence of the linker.
CJC-1295 is the name used for a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. The compound was described by a Canadian drug discovery company in the mid-2000s as a long-acting research tool. Two closely related molecules share the name in practice: one carries a drug affinity complex, or DAC, group, and one does not. The distinction matters because the two behave differently in circulation.
The peptide backbone corresponds to GRF(1-29), the first 29 residues of native growth hormone-releasing hormone, which retains most of the receptor-activating activity of the full-length molecule. Four substitutions distinguish the analog from the natural sequence: D-alanine at position 2, glutamine at position 8, alanine at position 15, and leucine at position 27. These changes slow cleavage by dipeptidyl peptidase IV, the enzyme that degrades native hormone in plasma within minutes. The outcome is improved enzymatic stability combined with a still brief residence time when no additional modification is present.
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.
Laminin G domain: all laminin alpha chains (LAMA1, LAMA2, LAMA3, LAMA4, LAMA5), cadherin EGF LAG seven-pass G-type receptors (CELSR1, CELSR2, CELSR3), contactin-associated proteins (CNTNAP1, CNTNAP2, CNTNAP3, CNTNAP3B, CNTNAP4, CNTNAP5), some collagens (COL5A1, COL5A3, COL9A1, COL11A1, COL11A2, COL12A1, COL14A1, COL15A1, COL16A1, COL18A1, COL19A1, COL20A1, COL21A1, COL22A1, COL24A1, COL27A1), crumbs homologs 1 and 2 (CRB1, CRB2), fat homologs (FAT1, FAT2, FAT3, FAT4), NEL-like proteins (NELL1, NELL2), neurexins (NRXN1, NRXN2, NRXN3), slit homologs (SLIT1, SLIT2, SLIT3), thrombospondins (THBS1, THBS2, THBS3, THBS4, TSPEAR), agrin (AGRIN), chondroitin sulfate proteoglycan 4 (CSPG4), eyes shut homolog (EYS), growth arrest-specific protein 6 (GAS6), perlecan (HSPG2), pikachurin (EGFLAM), protein S (PROS1), sex hormone-binding globulin (SHBG) and usherin (USH2A) Laminin N-terminal (domain VI): most laminin chains (LAMA1, LAMA2, LAMA3, LAMA5, LAMB1, LAMB2, LAMB3, LAMB4, LAMC1, LAMC3), most netrins (NTN1, NTN3, NTN4, NTNG1, NTNG2), and usherin (USH2A)
Gay-Lussac's law A chemical law used for each of the two relationships derived by French chemist Joseph Louis Gay-Lussac and which concern the properties of gases, though the name is more usually applied to his law of combining volumes.
There were three general dinosaur faunas in the Late Cretaceous. In the northern continents of North America and Asia, the major theropods were tyrannosaurids and various types of smaller maniraptoran theropods, with a predominantly ornithischian herbivore assemblage of hadrosaurids, ceratopsians, ankylosaurids, and pachycephalosaurians. In the southern continents that had made up the now-splitting supercontinent Gondwana, abelisaurids were the common theropods, and titanosaurian sauropods the common herbivores. Finally, in Europe, dromaeosaurids, rhabdodontid iguanodontians, nodosaurid ankylosaurians, and titanosaurian sauropods were prevalent. Flowering plants were greatly radiating, with the first grasses appearing by the end of the Cretaceous. Grinding hadrosaurids and shearing ceratopsians became very diverse across North America and Asia. Theropods were also radiating as herbivores or omnivores, with therizinosaurians and ornithomimosaurians becoming common. The Cretaceous–Paleogene extinction event, which occurred approximately 66 million years ago at the end of the Cretaceous, caused the extinction of all dinosaur groups except for the neornithine birds. Some other diapsid groups, including crocodilians, dyrosaurs, sebecosuchians, turtles, lizards, snakes, sphenodontians, and choristoderans, also survived the event.
== See also == Devil's Cigarette Lighter – a gas well fire that consumed 16 million cubic meters of gas per day. Environmental impact of war Gulf War oil spill Nuclear winter#Kuwait wells in the first Gulf War
=== Tau hypothesis of alzheimer's disease === The tau hypothesis states that excessive or abnormal phosphorylation of tau results in the transformation of normal adult tau into paired-helical-filament (PHF) tau and neurofibrillary tangles (NFTs). The stage of the disease determines NFTs' phosphorylation. In AD, at least 19 amino acids are phosphorylated; pre-NFT phosphorylation occurs at serine 199, 202 and 409, while intra-NFT phosphorylation happens at serine 396 and threonine 231. Through its isoforms and phosphorylation, tau protein interacts with tubulin to stabilize microtubule assembly. All of the six tau isoforms are present in an often hyperphosphorylated state in paired helical filaments (PHFs) in the AD brain. Tau mutations have many consequences, including microtubule dysfunction and alteration of the expression level of tau isoforms. Mutations that alter function and isoform expression of tau lead to hyperphosphorylation. The process of tau aggregation in the absence of mutations is not known but might result from increased phosphorylation, protease action or exposure to polyanions, such as glycosaminoglycans. Hyperphosphorylated tau disassembles microtubules and sequesters normal tau, MAPT 1 (microtubule associated protein tau 1), MAPT 2 and ubiquitin into tangles of PHFs. This insoluble structure damages cytoplasmic functions and interferes with axonal transport, which can lead to cell death. Hyperphosphorylated forms of tau protein are the main component of PHFs of NFTs in the brain of AD patients.
Sources: en.wikipedia.org
With the ability to form porous glasses as platelets, membrane technology is another important area of application. Hyper filtration of sea – and brackish water and ultra filtration in "downstream process" are but two. Additionally, they are often appropriate as a carrier for catalysts. For example, the olefin – metathesis was realized on the system metal – metal oxide/porous glass. Porous glasses can be used as membrane reactors as well, again because of their high mechanical, thermal and chemical stability. Membrane reactors can improve conversion of limited balance reactions, while one reaction product is removed by a selective membrane. For example, in the decomposition of hydrogen sulfide on a catalyst in a glass capillary, the conversion by reaction was higher with glass capillary than without.
=== As an antibiotic target === The sortases are thought to be good targets for new antibiotics as they are important proteins for pathogenic bacteria and some limited commercial interest has been noted by at least one company.
The more electropositive atoms tend to instead lose electrons, creating a "sea" of electrons engulfing cations. The outer orbitals of one atom overlap to share electrons with all its neighbours, creating a giant structure of molecular orbitals extending over all the atoms. This negatively charged "sea" pulls on all the ions and keeps them together in a metallic bond. Elements forming such bonds are often called metals; those which do not are often called nonmetals. Some elements can form multiple simple substances with different structures: these are called allotropes. For example, diamond and graphite are two allotropes of carbon. The metallicity of an element can be predicted from electronic properties. When atomic orbitals overlap during metallic or covalent bonding, they create both bonding and antibonding molecular orbitals of equal capacity, with the antibonding orbitals of higher energy. Net bonding character occurs when there are more electrons in the bonding orbitals than there are in the antibonding orbitals. Metallic bonding is thus possible when the number of electrons delocalized by each atom is less than twice the number of orbitals contributing to the overlap. This is the situation for elements in groups 1 through 13; they also have too few valence electrons to form giant covalent structures where all atoms take equivalent positions, and so almost all of them metallise. The exceptions are hydrogen and boron, which have too high an ionisation energy.
== Legacy == The song Rock Star by Reece Mastin references "Eddie Vedder." "Eddie Vedder" features the lyrics, "If I was Eddie Vedder, would you like me any better?" while "Rock Star," in turn, features the lyrics, "If I was Eddie Vedder, I'd bet you'd like me better"
=== Treatment of alcoholism === Apomorphine was one of the earliest used pharmacotherapies for alcoholism. The Keeley Cure (1870s to 1900) contained apomorphine, among other ingredients, but the first medical reports of its use for more than pure emesis come from James Tompkins and Charles Douglas. Tompkins reported, after injection of 6.5 mg ("one tenth of a grain"):In four minutes free emesis followed, rigidity gave way to relaxation, excitement to somnolence, and without further medication the patient, who before had been wild and delirious, went off into a quiet sleep.Douglas saw two purposes for apomorphine:[it can be used to treat] a paroxysm of dipsomania [an episode of intense alcoholic craving]... in minute doses it is much more rapidly efficient in stilling the dipsomaniac craving than strychnine or atropine… Four or even 3m [minim – roughly 60 microlitres] of the solution usually checks for some hours the incessant demands of the patient… when he awakes from the apomorphine sleep he may still be demanding alcohol, though he is never then so insistent as before. Accordingly it may be necessary to repeat the dose, and even to continue to give it twice or three times a day. Such repeated doses, however, do not require to be so large: 4 or even 3m is usually sufficient.This use of small, continuous doses (1/30th of a grain, or 2.16 mg by Douglas) of apomorphine to reduce alcoholic craving comes some time before Pavlov's discovery and publication of the idea of the "conditioned reflex" in 1903.
Sources: en.wikipedia.org
According to the records compiled by the United States Sentencing Commission, in 2009, the United States Department of Justice typically convicted a little over 81,000 people; of this, approximately 800 were convicted of money laundering as the primary or most serious charge. The Anti-Drug Abuse Act of 1988 expanded the definition of financial institution to include businesses such as car dealers and real estate closing personnel and required them to file reports on large currency transactions. It required verification of identity of those who purchase monetary instruments over $3,000. The Annunzio-Wylie Anti-Money Laundering Act of 1992 strengthened sanctions for BSA violations, required so called "Suspicious Activity Reports" and eliminated previously used "Criminal Referral Forms", required verification and recordkeeping for wire transfers and established the Bank Secrecy Act Advisory Group (BSAAG). The Money Laundering Suppression Act from 1994 required banking agencies to review and enhance training, develop anti–money laundering examination procedures, review and enhance procedures for referring cases to law enforcement agencies, streamline the currency transaction report exemption process, required each money services business (MSB) to be registered by an owner or controlling person, required every MSB to maintain a list of businesses authorized to act as agents in connection with the financial services offered by the MSB, made operating an unregistered MSB a federal crime, and recommended that states adopt uniform laws applicable to MSBs.
== PSP in wild marine mammals == PSP has been implicated as a possible cause of sea otter mortality and morbidity in Alaska, as one of its primary prey items, the butter clam (Saxidomus gigantea) bioaccumulates saxitoxin as a chemical defense mechanism. In addition, ingestion of saxitoxin-containing mackerel has been implicated in the death of humpback whales. Additional cases where PSP was suspected as the cause of death in Mediterranean monk seals (Monachus monachus) in the Mediterranean Sea have been questioned due to lack of additional testing to rule out other causes of mortality.
dimer A molecular aggregate consisting of two subunits. The term is often used to describe a protein complex composed of two proteins, either the same protein (a homodimer) or different proteins (a heterodimer); or to an individual protein composed of two polypeptides. Compare monomer, trimer, and tetramer.
Often this is done with drugs produced by catalytic reduction, hydrogenation, oxidation, or the like, producing strong derivatives of morphine and codeine. Many morphine derivatives can also be manufactured using thebaine or codeine as a starting material. Replacement of the N-methyl group of morphine with an N-phenylethyl group results in a product that is 18 times more powerful than morphine in its opiate agonist potency. Combining this modification with the replacement of the 6-hydroxyl with a 6-methylene group produces a compound some 1,443 times more potent than morphine, stronger than the Bentley compounds such as etorphine (M99, the Immobilon tranquilliser dart) by some measures. Closely related to morphine are the opioids morphine-N-oxide (genomorphine), which is a pharmaceutical that is no longer in common use; and pseudomorphine, an alkaloid that exists in opium, both of which form as degradation products of morphine. As a result of the extensive study and use of this molecule, more than 250 morphine derivatives (also counting codeine and related drugs) have been developed since the last quarter of the 19th century. These drugs range from 25% the analgesic strength of codeine (or slightly more than 2% of the strength of morphine) to several thousand times the strength of morphine, to powerful opioid antagonists, including naloxone (Narcan), naltrexone (Trexan), diprenorphine (M5050, the reversing agent for the Immobilon dart) and nalorphine (Nalline). Some opioid agonist-antagonists, partial agonists, and inverse agonists are also derived from morphine.
=== Prenatal development === The prenatal portion of tissue-resident dermal macrophages is produced from yolk-sac derived precursors. The generation of dermal macrophages results from primitive haematopoiesis or definitive haematopoiesis. Primitive haematopoiesis allows the generation of yolk-sac derived macrophages and subsequent release into the foetal bloodstream for tissue infiltration and colonisation. The infiltration of the skin by yolk-sac derived macrophages occurs as soon as 8.5 days after fertilisation. Different gene expressions regulate this process. It is independent of the MYB gene and dependent on the PU.1 gene. Definitive haematopoiesis occurs from 11 days and onwards after fertilisation. Monocytes are produced from haematopoietic stem cells in the liver, and they subsequently infiltrate the skin via the foetal bloodstream. In this process, cytokines like CSF1 are essential in facilitating the differentiation of monocytes into tissue-resident dermal macrophages and their survival. Therefore, the differentiation of monocytes to dermal macrophages is CSF-1/CSF1R dependent. The level of dermal macrophages from prenatal development remains detectible through constant, slow proliferation.
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.
A maleimide moiety reacts with the thiol of cysteine-34, forming a covalent bond. The reaction occurs in circulation without enzymatic catalysis.