If you have been reading about GRF(1-29) 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.
Last reviewed on 2025-09-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic peptide | GHRH analog, not a steroid |
| Backbone length | 29 amino acids | Based on GRF(1-29) |
| Substitutions | Four positions | D-Ala2, Gln8, Ala15, Leu27 |
| Appearance | White to off-white powder | Typical lyophilized research material |
| Common synonyms | Modified GRF(1-29) | Usage varies between sources |
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.
Four amino acid substitutions separate the modified backbone from the parent GRF(1-29) sequence. These changes reduce recognition by dipeptidyl peptidase IV and related proteases, extending the interval before degradation. Development work in this area sought longer-acting GHRH analogs for endocrine investigation. Published descriptions treat the substitution set as a defining property of the core sequence, while the albumin-binding linker is described separately as an optional addition to that same backbone.
The core sequence keeps the receptor-binding region of GHRH while replacing four positions that are vulnerable to dipeptidyl peptidase-4 and other proteases. Substitutions at positions 2, 8, 15, and 27 raise metabolic stability relative to the natural hormone. The N-terminal residues remain essential for activity, so changes there generally lower potency. Molecular weight sits near 3368 daltons for the tetrasubstituted analog without the linker, while the albumin-binding form is heavier because of the added maleimide group.
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.
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.
Batch-to-batch consistency depends on solid-phase peptide synthesis and subsequent purification. Coupling efficiency, resin choice, and cleavage conditions all affect the final profile. Counter-ion content and moisture can shift the apparent mass of a batch. Documentation typically includes a certificate of analysis with chromatograms and spectra. Independent verification by a second laboratory is sometimes requested. Whether a given certificate reflects the actual vial contents depends on chain of custody. Analytical methods themselves carry uncertainty that should be stated alongside results.
Lyophilized material is typically stored at minus twenty degrees Celsius or lower. Keeping the vial dry and protected from light preserves peptide integrity. Repeated freeze-thaw cycles can cause aggregation or loss of activity. Once dissolved, solutions are generally kept at two to eight degrees Celsius. Stability data for reconstituted solutions vary, and long-term behavior is not fully established. Working aliquots reduce the number of times a stock container is opened.
CHO cells are the most common mammalian cell line used for mass production of therapeutic proteins such as monoclonal antibodies, used in 70% of therapeutic mAbs. They can produce recombinant protein on the scale of 3–10 grams per liter of culture. Products of CHO cells are suitable for human applications, as these mammalian cells perform human-like post-translational modifications to recombinant proteins, which is key to the functioning of several proteins. It is believed that CHO-K1 transgenic cells are characterized by higher monoclonal antibody expression at the expense of biomass accumulation, for example, based on CHO-K1, monoclonal antibody‑producing cell lines with productivity up to 6.5 grams per liter have been selected. Cell culture Drug development Preclinical development
The idea of Food Social Security stemmed from noticing various flaws inherent to the current food system such as malnutrition, food insecurity, farmers' precarity and environmental concerns. Globally, while enough food is produced to feed ten billion people, food systems are threatening both human health and environmental sustainability. Food bank demand is soaring throughout the world, and is in itself not seen as a long-term response to food insecurity. Poor nutrition is generally linked to lower incomes, causing one of the largest public health challenges for children, and a significant strain on healthcare systems. The three fundamental principles of Food Social Security are:
Another form of bioprinting involves an inkjet printer, which is primarily used in biomedical settings. This method prints detailed proteins and nucleic acids. Hydrogels are commonly selected as the bioink. Cells can be printed on to a selected surface media to proliferate and ultimately differentiate. A drawback of this printing method is the ability of the bioinks such as hydrogels to clog the printing nozzle, due to their high viscosity. Ideal inkjet bioprinting involves using a low polymer viscosity (ideally below 10 centipoise), low cell density (<10 million cells/mL), and low structural heights (<10 million cells/mL).
Sources: en.wikipedia.org
Another strategy for site-specific amine conjugation to proteins is to replace lysine residues with arginine residues (LDVs). If all lysines are depleted then the only remaining free amine is at the amino terminus (N-terminus) of the protein. In the case where the protein is an antibody Fc domain, a recombinant LDV Fc can still be purified using protein A. LDV Fc proteins fused with short peptide targeting sequences can be used to deliver conjugated payloads, including nanoparticles, to specific cell surface proteins. The majority of ADCs under development or in clinical trials are for oncological and hematological indications. This is primarily driven by the inventory of monoclonal antibodies, which target various types of cancer. However, some developers are looking to expand the application to other important disease areas.
Naked extracellular DNA (eDNA), most of it released by cell death, is nearly ubiquitous in the environment. Its concentration in soil may be as high as 2 μg/L, and its concentration in natural aquatic environments may be as high at 88 μg/L. Various possible functions have been proposed for eDNA: it may be involved in horizontal gene transfer; it may provide nutrients; and it may act as a buffer to recruit or titrate ions or antibiotics. Extracellular DNA acts as a functional extracellular matrix component in the biofilms of several bacterial species. It may act as a recognition factor to regulate the attachment and dispersal of specific cell types in the biofilm; it may contribute to biofilm formation; and it may contribute to the biofilm's physical strength and resistance to biological stress. Cell-free fetal DNA is found in the blood of the mother, and can be sequenced to determine a great deal of information about the developing fetus. Under the name of environmental DNA eDNA has seen increased use in the natural sciences as a survey tool for ecology, monitoring the movements and presence of species in water, air, or on land, and assessing an area's biodiversity.
Increased health awareness: Regular testing can help individuals identify health trends and potential issues early, enabling proactive health management. Convenience and accessibility: At-home collection and direct ordering eliminate barriers such as scheduling appointments, obtaining referrals, and taking time off work. Cost transparency: Upfront pricing allows consumers to make informed decisions about testing costs. Patient empowerment: Direct access to health data supports informed decision-making and engagement in personal health management. In 2014 the federal government issued a regulation directing clinical laboratories to provide individuals with access to their test data upon request.
The Department works at the intersection of organic chemistry (chemistry of natural products, chemistry of macrocyclic compounds, chemistry of elementorganic compounds), supramolecular chemistry (solution and self-process chemistry) and molecular biology. The head of the Department is Professor Igor S. Antipin, a corresponding member of the Russian Academy of Science, Doctor of Chemistry. The Department conducts research in the following fields:
Sources: en.wikipedia.org
Professional APCs describe those APCs which are capable of delivering all 3 signals needed to activate a naive T cell (signal 1- the antigen itself, the peptide-MHC complex; signal 2 - costimulatory ligand; signal 3- cytokines to guide polarization of the T cell). Canonically, the 3 pAPC types are dendritic cells, macrophages, and B cells. They are very efficient at internalizing antigens, either by phagocytosis (e.g. macrophages), or by receptor-mediated endocytosis (B cells), processing the antigen into peptide fragments and then displaying those peptides (bound to a class II MHC molecule) on their membrane. The T cell recognizes and interacts with the antigen-class II MHC molecule complex on the membrane of the antigen-presenting cell. An additional co-stimulatory signal is then produced by the antigen-presenting cell, leading to activation of the T cell. The expression of co-stimulatory molecules and MHC class II are defining features of professional APCs. All professional APCs also express MHC class I molecules as well. The main types of professional antigen-presenting cells are dendritic cells, macrophages and B cells.
TBR1 was identified in 1995 by the Nina Ireland Laboratory of Developmental Neurobiology Center at the University of California, San Francisco. The gene, initially named TES-56, was found to be largely expressed in the telencephalic vesicles of the developing forebrain of mice. The protein product of TES-56 was discovered to be homologous to the Brachyury protein, a T-box transcription factor, which plays a role in establishing symmetry during embryonic development. Thus, due to its relation to T-box genes (such as Tbx-1, Tbx-2, Tbx-3), TES-56 was renamed TBR1. The human TBR1 gene is located on the q arm of the positive strand of chromosome 2. It is 8,954 base pairs in length. TBR1 is one of the three genes that make up the TBR1 subfamily of T-box genes. The two other genes that form the TBR1 subfamily are EOMES (also known as TBR2) and TBX21 (also known as T-BET). TBR1 is also known as T-box Brain Protein, T-Brain 1, and TES-56. The encoded protein consists of 682 amino acid residues and has a predicted molecular weight of 74,053 Da. It is composed of 6 exons.
Christopher A. Lipinski is a medicinal chemist who is working at Pfizer, Inc. He is known for his "rule of five", an algorithm that predicts drug compounds that are likely to have oral activity. By the number of citations, he is the most cited author of some pharmacology journals: Journal of Pharmacological and Toxicological Methods, Advanced Drug Delivery Reviews, Drug Discovery Today: Technologies. Lipinski received his PhD from the University of California, Berkeley in 1968 in physical organic chemistry. The Advanced Drug Delivery Reviews article reporting his "rule of five" is one of the most cited publications in the journal's history. In 2006, he received an honorary law degree from the University of Dundee and he has won various awards, including being the Society for Biomolecular Sciences' winner of the 2006 SBS Achievement Award for Innovation in HTS.
Analysis of CRISPR sequences revealed coevolution of host and viral genomes. The basic model of CRISPR evolution is newly incorporated spacers driving phages to mutate their genomes to avoid the bacterial immune response, creating diversity in both the phage and host populations. To resist a phage infection, the sequence of the CRISPR spacer must correspond perfectly to the sequence of the target phage gene. Phages can continue to infect their hosts' given point mutations in the spacer. Similar stringency is required in PAM or the bacterial strain remains phage sensitive.
In healthy individuals, the cortisol level should increase above 18–20 μg/dl within 60 minutes on a 250 mcg cosyntropin stimulation test. For standardization across laboratories, the Short Synacthen Test is preferably performed in the morning (between 8:00 AM and 10:00 AM) to account for the diurnal peak of cortisol secretion. Baseline cortisol is drawn at time 0, with follow‑up samples at 30 minutes (and optionally 60 minutes) after administration of 250 μg synthetic ACTH. An adequate response is generally defined as a peak serum cortisol ≥ 500–550 nmol/L (approximately 18–20 μg/dL) or an increment ≥ 200 nmol/L, thresholds that improve diagnostic accuracy for adrenal insufficiency. Interpretation for primary adrenal insufficiency, Addison's disease In Addison's disease, both the cortisol and aldosterone levels are low, and the cortisol will not rise during the cosyntropin stimulation test.
Sources: en.wikipedia.org
No. It is a laboratory-made analog of growth hormone-releasing hormone. The natural hormone is a 44-residue peptide, while the analog is built on a shorter 29-residue fragment.
The original material included a linker that binds serum albumin. A later variant removed that linker to reduce the duration of action. Catalogs and papers did not consistently adopt separate names, so both remain widely labeled with the same term.
The amino acid sequence and the presence or absence of the linker group. Mass measured by spectrometry gives an independent check that separates the two forms.
The version carrying the affinity complex bears a maleimide group that binds serum albumin, which extends its circulation time to several days. The version without it lacks this group and clears within roughly half an hour. The two are chemically related but behave very differently once in the body.