Reversed-phase HPLC 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.
Last reviewed on 2025-09-12. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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 |
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 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.
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.
While accepting an Honorary César in February 2026, Carrey revealed that he was in a long-term relationship with a woman named Min Ah, whom he called his "sublime companion." Seven months later, the couple were married in a private ceremony.
However, its toxicity to microorganisms is not overtly observed since the free silver ion is found in low concentrations in wastewater treatment systems and the natural environment due to its complexation with ligands such as chloride, sulfide, and thiosulfate.
The board of governors is the ultimate governing body of LLNS and is charged with overseeing the affairs of LLNS in its operations and management of LLNL. LLNS managers and employees who work at LLNL, up to and including the president and laboratory director, are generally referred to as laboratory employees. All laboratory employees report directly or indirectly to the LLNS president. While most of the work performed by LLNL is funded by the federal government, laboratory employees are paid by LLNS, which is responsible for all aspects of their employment, including providing health care benefits and retirement programs. Within the board of governors, authority resides in the executive committee to exercise all rights, powers, and authorities of LLNS, excepting only certain decisions that are reserved to the parent companies. The LLNS executive committee is free to appoint officers or other managers of LLNS and LLNL, and may delegate its authorities as it deems appropriate to such officers, employees, or other representatives of LLNS/LLNL. The executive committee may also retain auditors, attorneys, or other professionals as necessary. For the most part the executive committee has appointed senior managers at LLNL as the primary officers of LLNS. As a practical matter most operational decisions are delegated to the president of LLNS, who is also the laboratory director.
Biohazardous safety issues are identified with specified labels, signs and paragraphs established by the American National Standards Institute (ANSI). Today, ANSI Z535 standards for biohazards are used worldwide and should always be used appropriately within ANSI Z535 Hazardous Communications (HazCom) signage, labeling and paragraphs. The goal is to help workers rapidly identify the severity of a biohazard from a distance and through colour and design standardization. Biological hazard symbol design:
Sources: en.wikipedia.org
Bexagliflozin, sold under the brand name Brenzavvy, is an antidiabetic medication used to improve glycemic control in adults with type 2 diabetes. It is a sodium-glucose cotransporter 2 (SGLT2) inhibitor that is taken by mouth. The most common side effects include genital yeast infections, urinary tract infections, and increased urination. Bexagliflozin was approved for medical use in the United States in January 2023.
In November 2008, the Department of State said that finding the culprit was less important than "to get both sides, particularly the Russians, to live up to their obligations". On 9 September 2008, Chair of the House Foreign Affairs Committee Howard Berman stated in hearing of the United States House Committee on Foreign Affairs that Russia had been provoking Georgia and Saakashvili was compelled to respond to an ethnic cleansing of Georgians in South Ossetia. Berman continued that Russian actions revealed that Russia's real aim was not protection of the Russian citizens. On 9 September 2008, Assistant Secretary of State for European and Eurasian Affairs Daniel Fried said in hearing of the House Committee on Foreign Affairs that Russia had been provoking Georgia and Russia's actual aim was to change the borders of the sovereign nation. Fried further described the events on the night of August 7 and reported that the Georgians had reported the entry of the Russian forces into the Roki Tunnel. Fried said that the US administration clearly "pointed out that use of military force [by Georgia], even in the face of provocations, would lead to a disaster." Fried stated that "one fact is clear—there was no justification for Russia's invasion of Georgia." When Fried was asked why Georgian leadership ignored his clear advice not to resort to military force, he replied that Georgia "had been provoked for a long period of time" by the opposing sides.
Validation activities are conducted to ensure that the resulting products and services meet the requirements for the specified application or intended use. Verification activities are conducted to ensure that the design and development outputs meet the input requirements. It also notes that verification and validation have distinct purposes but can be conducted separately or in any combination, as is suitable for the products and services of the organization. The National Institute of Standards and Technology Information Technology Laboratory Computer Security Resource Center has a variety of definitions for both validation and verification
Sources: en.wikipedia.org
March 14 – Marvin Scott died on March 14, 2021, in police custody at a correctional facility in McKinney, Texas. March 14–15 – A blizzard in Colorado brings over 24.1 inches (61 cm) of snow, passing a record of 23.8 inches (60 cm) set in 1982, to become the fourth largest recorded snowfall in Denver history and the largest since 2003 when the city received 31.8 inches (81 cm). It also leaves tens of thousands of people without power and some stranded in their cars after roads are closed. In Wyoming, over 31 inches (79 cm) were received in Cheyenne, and 52.5 inches (133 cm) in the Laramie Range. March 15 – Three people are killed and one injured when a small plane crashes in Pembroke Pines, Florida. March 16 COVID-19 pandemic: Massachusetts confirms its first case of the Lineage P.1 variant that originated in Brazil. 2021 Atlanta spa shootings – Eight people are killed and one is injured in a trio of shootings at spas in the Metro Atlanta, Georgia area. A suspect is arrested 150 miles south of Atlanta later that day and charged with eight counts of murder and one count of attempted murder two days later, March 18. March 17 The IRS announces that the deadline for Tax Day will be postponed to May 17. COVID-19 pandemic: North Dakota confirms its first four cases of the California variant of SARS-CoV-2. Additionally, seven cases of the UK variant are also confirmed. March 18–19 – The U.S. and China hold talks in Alaska to discuss relations, with topics ranging from Taiwanese security to Black Lives Matter.
Efficiency factor (N) practically measures how sharp component peaks on the chromatogram are, as ratio of the component peak's area ("retention time") relative to the width of the peaks at their widest point (at the baseline). Peaks that are tall, sharp, and relatively narrow indicate that separation method efficiently removed a component from a mixture; high efficiency. Efficiency is very dependent upon the HPLC column and the HPLC method used. Efficiency factor is synonymous with plate number, and the 'number of theoretical plates'. Retention factor (kappa prime) measures how long a component of the mixture stuck to the column, measured by the area under the curve of its peak in a chromatogram (since HPLC chromatograms are a function of time). Each chromatogram peak will have its own retention factor (e.g., kappa1 for the retention factor of the first peak). This factor may be corrected for by the void volume of the column. Separation factor (alpha) is a relative comparison on how well two neighboring components of the mixture were separated (i.e., two neighboring bands on a chromatogram). This factor is defined in terms of a ratio of the retention factors of a pair of neighboring chromatogram peaks, and may also be corrected for by the void volume of the column. The greater the separation factor value is over 1.0, the better the separation, until about 2.0 beyond which an HPLC method is probably not needed for separation.
== Active site == The spherical carboxypeptidase domain of the catalytic subunit has a circular indentation in the surface which is the location of the active-site groove. The base of the groove is formed by 3 β-sheets while the walls of the groove are lined with α-helices. The electron density in the middle of the groove allows a space for the zinc ion cofactor to bind. The P1' residue of the substrate is placed in a specific cavity (S1') of the active-site groove while the P1 residues and on extend into a mostly hydrophobic area of the groove (in pockets S1, S2, etc.). The scissile peptide bond is held in place with several polar interactions between protein side groups. The nitrogen atom on the C-terminal side is anchored to the nearby guanidine groups of arginine molecules. On the N-terminal side, the nitrogen atom is held by hydrogen bonds with tyrosine while the carbonyl group is held by hydrogen bonds with lysine. These interactions stretch the peptide bond and set it up for the water molecule to break it apart. While there are technically two active sites on the tetramer, one on each active subunit, only one active site can be used at a time.
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.
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.