The short version of GRF(1-29) fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-14. Anything still debated is marked as such rather than presented as settled.
Identity and purity are established with reversed phase high performance liquid chromatography coupled to mass spectrometry. The chromatographic step separates the target peptide from truncated sequences and deletion products, while the mass measurement confirms the expected molecular weight to within a fraction of a dalton. Because the two common variants differ by the presence of the linker, mass alone can distinguish them in the unconjugated state. Amino acid analysis and peptide mapping are used when sequence level confirmation is required.
Lyophilized material is generally stable for extended periods when held at minus twenty degrees Celsius or below and protected from moisture and light. In solution the peptide is more labile; bond hydrolysis, aggregation and oxidation of susceptible residues all proceed faster at ambient temperature. Repeated freeze and thaw cycles should be avoided because they promote clumping and loss of soluble material. The conjugated variant adds a further consideration, since the maleimide group can hydrolyze in aqueous buffer and lose its ability to react with albumin.
CJC-1295 is a synthetic peptide built as a long-acting analogue of growth hormone-releasing hormone. Its backbone matches the first twenty-nine residues of the natural human hormone, with four amino acid substitutions added to slow enzymatic breakdown. A reactive maleimide group, commonly termed the drug affinity complex, allows the peptide to attach to circulating albumin after administration. That albumin attachment keeps the molecule in the bloodstream for an extended period instead of being cleared within minutes.
The compound emerged from work at a Canadian biotechnology firm in the early 2000s. Early human studies examined its effect on growth hormone and insulin-like growth factor 1 in healthy volunteers and in people with HIV-associated fat redistribution. Reports described sustained increases in both markers after a single injection. Development did not advance to regulatory approval, and the clinical programme was later discontinued. The molecule is now encountered mainly as a research chemical rather than a marketed medicine.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off white powder | Typical lyophilized form |
| Water solubility | Soluble | May need a small organic co-solvent |
| Purity assessment | Chromatographic peak area | Most certificates report a percentage figure |
| Storage temperature | Minus 20 C or lower | Dry, dark, sealed container |
| Identity check | Electrospray mass spectrometry | Compared against theoretical mass |
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.
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.
Analytical confirmation usually relies on reversed-phase high-performance liquid chromatography for purity and on liquid chromatography coupled to mass spectrometry for identity. Mass data reveal the expected molecular mass and can flag truncated or oxidized species. Amino acid analysis and peptide mapping provide sequence-level verification. Immunoassays are used in some biological matrices, but antibodies raised against one releasing-hormone analog may cross-react with another. Reported purity figures depend heavily on the method used, so comparisons between suppliers require matching the analytical approach.
The two variants differ dramatically in how long they persist in circulation. The form lacking the albumin-binding group has a plasma half-life measured in tens of minutes, comparable to the natural hormone fragment. The version carrying the drug affinity complex binds albumin and shows a half-life of roughly six to eight days in human studies. That figure comes from small trials that tracked hormone levels over extended periods. The physiological consequences of sustained versus pulsatile stimulation are still debated and the literature does not settle the point.
Lyophilized peptide powder is comparatively stable when kept dry, cold, and protected from light. Once dissolved, the molecule is vulnerable to deamidation, oxidation, and aggregation, with the rate depending on pH, buffer composition, and temperature. Alkaline conditions and repeated freeze-thaw cycles accelerate loss of the intact peptide. The methionine present in the native sequence is a known oxidation site, which is one reason it was replaced in the modified fragment. Suppliers typically recommend cold storage of solutions and use within a short window.
Listing of strengths of common acids and bases Zumdahl, Steven S. (1997). Chemistry (4th ed.). Boston: Houghton Mifflin. ISBN 9780669417944. Pavia, D. L.; Lampman, G. M.; Kriz, G. S. (2004). Organic Chemistry Volume I. Mason, OH: Cengage Learning. ISBN 0759347271.
== History == IMS was first developed primarily by Earl W. McDaniel of Georgia Institute of Technology in the 1950s and 1960s when he used drift cells with low applied electric fields to study gas phase ion mobilities and reactions. In the following decades, he integrated the recently developed technology he had been working on with a magnetic-sector mass spectrometer. During this period, others also utilized his techniques in novel and original ways. Since then, IMS cells have been included in various configurations of mass spectrometers, gas chromatographs, and high-performance liquid chromatography instruments. IMS is a method used in multiple contexts, and the breadth of applications that it can support, in addition to its capabilities, is continually being expanded.
Modern non-avian reptiles exhibit some form of cold-bloodedness (i.e. some mix of poikilothermy, ectothermy, and bradymetabolism) so that they have limited physiological means of keeping the body temperature constant and often rely on external sources of heat. Due to a less stable core temperature than birds and mammals, reptilian biochemistry requires enzymes capable of maintaining efficiency over a greater range of temperatures than in the case for warm-blooded animals. The optimum body temperature range varies with species, but is typically below that of warm-blooded animals; for many lizards, it falls in the 24–35 °C (75–95 °F) range, while extreme heat-adapted species, like the American desert iguana Dipsosaurus dorsalis, can have optimal physiological temperatures in the mammalian range, between 35 and 40 °C (95 and 104 °F). While the optimum temperature is often encountered when the animal is active, the low basal metabolism makes body temperature drop rapidly when the animal is inactive. As in all animals, reptilian muscle action produces heat. In large reptiles, like leatherback turtles, the low surface-to-volume ratio allows this metabolically produced heat to keep the animals warmer than their environment even though they do not have a warm-blooded metabolism. This form of homeothermy is called gigantothermy; it has been suggested as having been common in large dinosaurs and other extinct large-bodied reptiles. The benefit of a low resting metabolism is that it requires far less fuel to sustain bodily functions.
Sources: en.wikipedia.org
The α-globin chains are encoded by two closely linked genes HBA1 and HBA2 on chromosome 16; in a person with two copies on each chromosome, a total of four loci encode the α chain. Two alleles are maternal and two alleles are paternal in origin. Alpha-thalassemias result in decreased alpha-globin production, resulting in an excess of β chains in adults and excess γ chains in fetus and newborns.
endocytosis Any process by which a substance is actively uptaken by or brought inside of a cell, crossing the plasma membrane from an extracellular space into an intracellular space, which includes the subclasses of pinocytosis, phagocytosis, and receptor-mediated processes. All of these involve surrounding an extracellular molecule, protein, or even another cell or organism with an extension or invagination of the cell membrane, which then "buds off" or separates from the rest of the membrane on the cytoplasmic side, forming a membrane-enclosed vesicle containing the ingested materials. By this mechanism the material can cross the lipid bilayer without being exposed to the hydrophobic space in between, instead remaining suspended in the fluid of the extracellular space. Many large, polar macromolecules which cannot simply diffuse across the membrane, such as metabolites and hormones, are transported into the cell by endocytosis. It is distinguished from alternative routes such as passing through protein channels or being chaperoned by transport proteins. The reverse process is called exocytosis.
DNA sequencing, one of the most fundamental technologies developed to study genetics, allows researchers to determine the sequence of nucleotides in DNA fragments. The technique of chain-termination sequencing, developed in 1977 by a team led by Frederick Sanger, is still routinely used to sequence DNA fragments. Using this technology, researchers have been able to study the molecular sequences associated with many human diseases. As sequencing has become less expensive, researchers have sequenced the genomes of many organisms using a process called genome assembly, which uses computational tools to stitch together sequences from many different fragments. These technologies were used to sequence the human genome in the Human Genome Project completed in 2003. New high-throughput sequencing technologies are dramatically lowering the cost of DNA sequencing, with many researchers hoping to bring the cost of resequencing a human genome down to a thousand dollars. Next-generation sequencing (or high-throughput sequencing) came about due to the ever-increasing demand for low-cost sequencing. These sequencing technologies allow the production of potentially millions of sequences concurrently. The large amount of sequence data available has created the subfield of genomics, research that uses computational tools to search for and analyze patterns in the full genomes of organisms. Genomics can also be considered a subfield of bioinformatics, which uses computational approaches to analyze large sets of biological data.
== Services == The Instituto Universitario de Restauración del Patrimonio is divided into two areas: the area of intervention in the Pictorial and Sculptural Heritage and the area of intervention in the Architectural Heritage, and a Training and Dissemination area. The area of intervention in the pictorial and sculptural heritage operates in both basic research and applied research in seeking to acquire new knowledge to develop new products, techniques, processes, methods and systems that improve existing ones. The area of intervention in the Pictorial and Sculptural Heritage consist in restoration workshops:
Sources: en.wikipedia.org
The mass difference from the linker is large enough for routine detection by mass spectrometry. The unconjugated form gives a single sharp signal at its expected weight. Material that has already reacted with albumin shows a much higher mass and a broadened chromatographic peak.
Yes. Degradation proceeds faster once the powder is dissolved, especially at room temperature or after multiple freeze and thaw cycles. Working solutions are often aliquoted to avoid repeated handling. Lyophilized powder held cold and dry retains its properties far longer.
Truncated sequences, oxidized residues and aggregated forms can all elute near the main peak. Reversed phase chromatography resolves many of these species, so the number of peaks is a useful indicator of synthesis quality. A single peak does not by itself prove correct sequence, which is why mass confirmation is paired with it.
It is a synthetic peptide analogue of growth hormone-releasing hormone. Four substitutions in its sequence make it more resistant to enzymatic degradation than the natural hormone. In the version carrying a drug affinity complex, the peptide binds albumin and remains in circulation for days.