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Structure And Receptor Pharmacology — Reference Sheet

By Editorial Desk · published 2026-01-27 · last reviewed 2026-03-20 · Wiki

Albumin binding comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.

Updated 2026-03-20. Numbers and descriptions here follow the published literature rather than marketing material.

Structure And Receptor Pharmacology

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.

Handling Storage And Analytical Methods

Research material is normally supplied as a freeze-dried powder in sealed vials. In that state the peptide is comparatively robust, but prolonged exposure to warmth, moisture, or light accelerates degradation. Storage at minus twenty degrees Celsius or lower, with desiccant and protection from light, is the commonly described practice. Vials should be allowed to reach room temperature before opening to limit condensation on the powder. Moisture uptake during handling is a recognized source of variability in later measurements.

Reconstitution is typically performed with sterile water or bacteriostatic water, added slowly against the vial wall. The resulting solution should be clear and colorless; cloudiness or visible particles suggest a problem with the material or the diluent. Once in solution, the peptide is less stable than the dry powder. Refrigerated storage at two to eight degrees Celsius is common for short-term holding, while freezing aliquots is described for longer periods.

Purity is most often assessed by reversed-phase high-performance liquid chromatography, reported as a percentage of total peak area. Identity is confirmed by mass spectrometry, which yields a molecular ion consistent with the expected sequence. Amino acid analysis and peptide mapping provide additional characterization. Reported purity values are method-dependent, so figures from different laboratories are not always directly comparable without details of column, gradient, and detection wavelength.

Cjc-1295 at a glance

PropertyValueNotes
Peptide classSynthetic GHRH analogueBuilt on a 29 residue sequence
Primary targetGHRH receptor (GHRHR)Class B G protein coupled receptor
Unconjugated half lifeMinutesLimited by protease degradation
Key modificationFour residue substitutionsPositions 2, 8, 15 and 27
Common synonymModified GRF(1-29)Usually denotes the form without DAC

Albumin Binding and Duration of Action

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.

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.

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Background and Molecular Features

CJC-1295 is a synthetic peptide modeled on growth hormone-releasing hormone, the hypothalamic signal that prompts the pituitary to release growth hormone. Its sequence corresponds to the first twenty-nine residues of human GHRH, with four substitutions that slow enzymatic breakdown. Early descriptions placed the compound in research on growth hormone deficiency and related conditions, and later literature groups it with the long-acting GHRH analogs. The name appears in both laboratory and popular fitness writing, where it sometimes labels chemically different peptides.

Two related peptides circulate under the CJC-1295 label, and they differ mainly in how long they persist in circulation. The version carrying a drug affinity complex includes a maleimidopropionic acid linker that forms a covalent bond with serum albumin. The other version, usually written as modified GRF(1-29) or tetrasubstituted GRF(1-29), lacks that linker and is cleared quickly. Mixing the two produces inconsistent readings of published half-life values, because the linker rather than the receptor-facing sequence drives most of the difference.

Notes from published material

=== Baptist === Baptist Life Association - Founded in 1884 as the German Baptist Life Association. Adopted current name in 1934. Had 1,158 members in 1911; at the time it readjusted its inadequate rate system. By 1921 this had grown to 2,639. In 1965 it had 12,335 members, in 1979 about 13,000 in 49 branches in 26 states. Had 12,705 members in 1994. Headquarters in Buffalo, New York. National convention meets quadrennially. Motto "Honoring God while serving Mankind". Offers scholarships ranging from $800 – $2,000. A "Branch match" program where the branch is given $100 for a parish project and the parish matches it. Home Bible studies prepared by Moody Bible Institute, summer family camping and Bible conferences, art and photo contests, etc.

===== The maxillary division innervation ===== Maxillary nerve – conveys sensation to the upper jaw and the face. Infraorbital nerve – conveys sensation to the area from below the eye socket to the external nares (nostrils). Zygomatic nerve – through the zygomatic bone and the zygomatic arch, conveys sensation to the cheekbone areas. Superior posterior dental nerve – sensation in the teeth and the gums. Superior anterior dental nerve – mediates the sneeze reflex. Sphenopalatine nerve – divides into the lateral branch and the septal branch, and conveys sensation from the rear and the central regions of the nasal cavity.

Hohhot Baita International Airport (IATA: HET, ICAO: ZBHH) is an international airport serving Hohhot, the capital of Inner Mongolia, China. It is the largest airport in Inner Mongolia and lies 14.3 km (8.9 mi) east of downtown Hohhot. Its name Baita, meaning White Pagoda, derives from Wanbu Huayanjing Pagoda; one of the historical attractions in Hohhot which lies 5.6 km (3.5 mi) south-east of the airport. In 2025 it served 12,722,692 passengers.

Sources: en.wikipedia.org

Background from the literature

The connecting peptide, or C-peptide, is a short 31-amino-acid polypeptide that connects insulin's A-chain to its B-chain in the proinsulin molecule. In the context of diabetes or hypoglycemia, a measurement of C-peptide blood serum levels can be used to distinguish between different conditions with similar clinical features. In the insulin synthesis pathway, first preproinsulin is translocated into the endoplasmic reticulum of beta cells of the pancreas as one polypeptide comprising the regions of the A-chain, C-peptide, B-chain, and signal sequence. The signal sequence is cleaved from the N-terminus of the peptide by a signal peptidase, leaving proinsulin. After proinsulin is packaged into vesicles in the Golgi apparatus (beta-granules), the C-peptide is removed, leaving the A-chain and B-chain bound together by disulfide bonds, that constitute the insulin molecule. C-peptide has virtually no affinity for the insulin receptor, however, it is known to promote the activity of at least two enzymes - the sodium–potassium pump and nitric oxide synthase - downstream of binding to a membrane structure (presumably a G protein-coupled receptor). Nevertheless, the physiological significance of these effects of C-peptide is unresolved.

Digestion of native collagen in the triple helical region at -Gly bonds. With synthetic peptides, a preference is shown for Gly at P3 and P1', Pro and Ala at P2 and P2', and hydroxyproline, Ala or Arg at P3' Six species of metalloendopeptidase acting on native collagen can be isolated from the medium of Clostridium histolyticum.

Fluoxetine, sold under the brand name Prozac, among others, is an antidepressant medication of the selective serotonin reuptake inhibitor (SSRI) class used for the treatment of major depressive disorder, anxiety, obsessive–compulsive disorder (OCD), panic disorder, premenstrual dysphoric disorder, and bulimia nervosa. It is also approved for treatment of major depressive disorder in adolescents and children eight years of age and over. It has also been used to treat premature ejaculation. Fluoxetine is taken by mouth. Common side effects of fluoxetine include loss of appetite, nausea, diarrhea, headache, trouble sleeping, dry mouth, and sexual dysfunction. In some patients, sexual dysfunction may persist even after the drug is discontinued, a condition known as post-SSRI sexual dysfunction. Serious side effects include serotonin syndrome, mania, seizures, an increased risk of suicidal behavior, and an increased risk of bleeding. Fluoxetine was invented by Eli Lilly and Company in 1972. Eli Lilly filed a new drug application for the US Food and Drug Administration in 1974, which was accepted in 1977. It subsequently entered medical use in 1986. It is on the World Health Organization's List of Essential Medicines and is available as a generic medication. In 2023, it was the eighteenth most commonly prescribed medication in the United States and the fourth most common antidepressant, with more than 27 million prescriptions.

Sources: en.wikipedia.org

Further detail

=== Category:EC 1.14 (act on paired donors with incorporation of molecular oxygen) === Cytochrome P450 oxidase Category:Cytochrome P450 Aromatase EC 1.14.14.1 CYP2D6 EC 1.14.14.1 CYP2E1 EC 1.14.14.1 CYP3A4 EC 1.14.14.1 Cytochrome P450 oxidase Category:EC 1.14.12 Nitric oxide dioxygenase Category:EC 1.14.13 Nitric oxide synthase EC 1.14.13.39 Category:EC 1.14.14 Aromatase EC 1.14.14.1 CYP2D6 EC 1.14.14.1 CYP2E1 EC 1.14.14.1 CYP3A4 EC 1.14.14.1 Category:EC 1.14.16 Phenylalanine hydroxylase EC 1.14.16.1 Category:EC 1.14.18 Tyrosinase EC 1.14.18.1

The parenteral route is any route that is not enteral (par- + enteral). Parenteral administration can be performed by injection, that is, using a needle (usually a hypodermic needle) and a syringe, or by the insertion of an indwelling catheter. Locations of application of parenteral administration include:

In this case, once the vapor layer is established, cooling never collapses the layer, and no nucleate boiling occurs; the layer instead slowly relaxes until the surface is cooled. Droplets of different liquids with different boiling temperatures will also exhibit a Leidenfrost effect with respect to each other and repel each other. The Leidenfrost effect has been used for the development of high sensitivity ambient mass spectrometry. Under the influence of the Leidenfrost condition, the levitating droplet does not release molecules, and the molecules are enriched inside the droplet. At the last moment of droplet evaporation, all the enriched molecules release in a short time period and thereby increase the sensitivity. A heat engine based on the Leidenfrost effect has been prototyped; it has the advantage of extremely low friction. The effect also applies when the surface is at room temperature but the liquid is cryogenic, allowing liquid nitrogen droplets to harmlessly roll off exposed skin. Conversely, the inverse Leidenfrost effect lets drops of relatively warm liquid levitate on a bath of liquid nitrogen.

Sources: en.wikipedia.org

Frequently asked questions

Is CJC-1295 the same as modified GRF(1-29)?

The names are often used interchangeably in casual writing, but they are not strictly identical. Modified GRF(1-29) refers to the unconjugated analogue carrying only the four substitutions. The version sold as CJC-1295 with DAC includes the albumin binding linker and clears much more slowly.

What does the acronym DAC refer to?

DAC stands for drug affinity complex, a term describing the maleimidopropionic acid linker. This group forms a covalent bond with the cysteine residue on serum albumin after administration. The resulting adduct is what extends the circulating half life from minutes to days.

Does this peptide occur naturally in the body?

No. It is entirely synthetic and does not correspond to any known endogenous peptide. The design starts from human growth hormone releasing hormone and introduces deliberate substitutions. Any biological effect comes from mimicking the natural hormone at its receptor.

How should the dry powder be stored?

Cool, dark, and dry conditions are standard, with storage at minus twenty degrees Celsius or below. Desiccant and sealed vials limit moisture uptake. Repeated warming and cooling of the container is generally avoided.

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