This is a working overview of circadian rhythm, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-01-01 and is reviewed periodically as new material appears.
Regulatory status varies by country and intended use. Major drug agencies have not granted marketing authorization for SR9009 as a medicine, and it is not listed as a controlled substance in many jurisdictions. It is often sold as a research chemical, a category that may fall outside pharmaceutical manufacturing rules. Buyers should verify local laws and supplier documentation, including certificates of analysis. The lack of standardized quality controls raises concerns about identity, purity, and actual content in products marketed online.
In laboratory settings, SR9009 is commonly identified by its molecular structure and its interaction with REV-ERB receptors. Vendors may list it under synonyms such as Stenabolic or REV-ERB agonist, but those names do not define purity or identity. Analytical confirmation typically uses high-performance liquid chromatography with ultraviolet detection or liquid chromatography–mass spectrometry. A reference standard is needed to compare retention time and mass spectrum, because the compound can be confused with related research chemicals.
Handling practices for SR9009 focus on minimizing degradation and contamination. The solid is generally stored desiccated at or below -20 °C, protected from light and moisture. Stock solutions are often prepared in dimethyl sulfoxide or ethanol, then aliquoted to avoid repeated freeze–thaw cycles. Aqueous solubility is low, so formulations for animal studies may require cosolvents or suspending agents. Personnel should follow institutional chemical safety procedures, because toxicological data for humans are incomplete.
SR9009 binds REV-ERB receptors and alters their repressive activity on target genes. This action can change transcription of genes involved in lipid handling, glucose metabolism, and mitochondrial function. In rodent studies, treated animals have shown changes in muscle oxidative capacity and exercise performance, though effects vary by dose, duration, and model. The precise molecular steps connecting receptor binding to whole-body outcomes are still an active area of investigation. Findings in animals do not automatically translate to humans.
Because REV-ERB receptors are core clock components, SR9009 has been examined for effects on daily rhythms as well as metabolism. Research has explored whether the compound can shift or reinforce circadian gene expression in tissues such as liver and muscle. Some studies report improved metabolic markers in obese or diabetic mice, while others show context-dependent responses. Questions remain about which effects are direct, which are secondary to timing, and how they might differ across species.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white solid | Visual inspection is not sufficient for identity. |
| Solubility | Soluble in DMSO and ethanol | Low solubility in water. |
| Typical storage | -20 °C, desiccated, dark | Protect from repeated temperature changes. |
| Common analytical method | LC-MS or HPLC-UV | Reference standard required for comparison. |
| Common synonyms | SR9009; Stenabolic; REV-ERB agonist | Vendor naming may vary. |
Regulatory and sporting contexts treat SR9009 as a prohibited substance in many elite competitions. Its presence on banned lists reflects concerns about performance enhancement and unknown long-term safety. Analytical chemists have developed methods to detect the parent compound and its metabolites in urine and blood. Literature discussions distinguish between in vitro potency, animal pharmacology, and anecdotal human reports. The latter are difficult to verify because products sold online may lack purity or contain different compounds.
SR9009 is a synthetic small molecule studied as an agonist of the nuclear receptors REV-ERBα and REV-ERBβ. These receptors help regulate circadian rhythms, lipid metabolism, and inflammatory gene expression. In cell and animal experiments, SR9009 alters transcription of clock-controlled genes and metabolic pathways. The compound is not a hormone and does not resemble classical steroid structures. Its activity depends on binding to the ligand-binding domain of REV-ERB, where it can modify corepressor recruitment.
SR9009 is frequently discussed in fitness and research-chemical contexts, yet it has no approved medical indication. Regulatory agencies have not authorized it for human use, and it is not a standard prescription drug. Some sports organizations list it as a prohibited substance because of its potential performance-enhancing properties. Published human data are sparse, so claims about its effects in people often rely on animal models or anecdotal reports. Quality and identity of online materials can vary widely.
SR9009 is a synthetic small molecule studied as a REV-ERB agonist. REV-ERBα and REV-ERBβ are nuclear receptors that help regulate circadian rhythms and metabolic gene expression. The compound was identified in academic screening efforts to find synthetic ligands for these receptors. In cell and animal studies, SR9009 alters transcription of genes involved in lipid and glucose metabolism, and it can shift circadian behavior. It is not an approved therapeutic agent.
Treating Type 2 Diabetes with glucose mimetics Mason found the common denominator between gastric and intestinal bypass when treating type 2 diabetes in 1998. The exposure of the distal bowel to glucose or other stimulants such as glucose mimetics resulted in the secretion of GLP-1 (glucagon-like peptide-1) hormones, which could potentially treat diabetes type-2 disease. Gastric bypass surgery treated type-2 diabetes through weight loss and the release of GLP-1 hormones. To treat diabetes-type 2 patients without surgery, he thought that using a form of glucose substitute or glucose mimetic that would reach the distal ileum before it was absorbed could be a simple and cost-effective treatment. He suggested using glucose mimetic d-tagatose in addition to weight reduction with a proper diet and increased physical activity.
The tumor-suppressor protein p53 accumulates when DNA is damaged due to a chain of biochemical factors. Part of this pathway includes alpha-interferon and beta-interferon, which induce transcription of the p53 gene, resulting in the increase of p53 protein level and enhancement of cancer cell-apoptosis. p53 prevents the cell from replicating by stopping the cell cycle at G1, or interphase, to give the cell time to repair; however, it will induce apoptosis if damage is extensive and repair efforts fail. Any disruption to the regulation of the p53 or interferon genes will result in impaired apoptosis and the possible formation of tumors.
I was expecting to retrieve the body from a fridge in the mortuary, but... it was stored in a body bag that was kept on the floor of a garage away from the main hospital building. She was in a transparent body bag packed with wood shavings and sawdust. There was also some kind of liquid and I remember that I was frightened that the bag would split open. The body was covered in sores and scars – it was quite horrific. I was on my own and I needed help to lift the body... but I managed to get her into the van. People from the hospital were very wary of helping me... When the day of the funeral arrived, the cars were given an escort by unmarked police vehicles just in case there was an accident... The body had to be cremated because there was a chance the virus could have thrived in the ground if Mrs Parker had been buried. All other funerals were cancelled that day and the Robin Hood Crematorium was thoroughly cleaned afterwards. Concerns over the survival of infectious virus in Parker's body were well-founded, and at the inquest the coroner, who signed Parker's cremation certificate, disallowed an autopsy for safety reasons.
The citric acid cycle is regulated mainly by the availability of key substrates, particularly the ratio of NAD+ to NADH and the concentrations of calcium, inorganic phosphate, ATP, ADP, and AMP. Citrate – the ion that gives its name to the cycle – is a feedback inhibitor of citrate synthase and also inhibits PFK, providing a direct link between the regulation of the citric acid cycle and glycolysis.
Sources: en.wikipedia.org
Network Science, Part 5: Solvent-Accessible Surfaces AREAIMOL is a command line tool in the CCP4 Program Suite for calculating ASA. NACCESS solvent accessible area calculations. FreeSASA Open source command line tool, C library and Python module for calculating ASA. Surface Racer Oleg Tsodikov's Surface Racer program. Solvent accessible and molecular surface area and average curvature calculation. Free for academic use. ASA.py — a Python-based implementation of the Shrake-Rupley algorithm. Michel Sanner's Molecular Surface – the fastest program to calculate the excluded surface. pov4grasp render molecular surfaces. Molecular Surface Package — Michael Connolly's program. Volume Voxelator — A web-based tool to generate excluded surfaces. ASV freeware Analytical calculation of the volume and surface of the union of n spheres (Monte-Carlo calculation also provided). Vorlume Computing Surface Area and Volume of a Family of 3D Balls. GetArea Calculate solvent accessible surface area of proteins online. ProMS ProMS - Protein Molecular Surface Calculator
This type of specificity is sensitive to the substrate's optical activity of orientation. Stereochemical molecules differ in the way in which they rotate plane polarized light, or orientations of linkages (see alpha, beta glycosidic linkages). Enzymes that are stereochemically specific will bind substrates with these particular properties. For example, beta-glycosidase will only react with beta-glycosidic bonds which are present in cellulose, but not present in starch and glycogen, which contain alpha-glycosidic linkages. This is relevant in how mammals are able to digest food. For instance, the enzyme Amylase is present in mammal saliva, that is stereo-specific for alpha-linkages, this is why mammals are able to efficiently use starch and glycogen as forms of energy, but not cellulose (because it is a beta-linkage). Specific equilibrium dissociation constant for formation of the enzyme-substrate complex is known as k d {\displaystyle k_{d}}
Parker was born in March 1938, and was the only daughter of Frederick and Hilda Witcomb (née Linscott). She was married to Joseph Parker, a Post Office engineer, and lived in the Kings Norton area of Birmingham. After several years as a police photographer, she joined the University of Birmingham Medical School, where she was employed as a medical photographer in the Anatomy Department. She often worked in a darkroom above the laboratory where research on smallpox viruses was being conducted.
Prior to the Air Pollution Control Act of 1955, little headway was made to initiate this air pollution reform. U.S. cities Chicago and Cincinnati first established smoke ordinances in 1881. In 1904, Philadelphia passed an ordinance limiting the amount of smoke in flues, chimneys, and open spaces. The ordinance imposed a penalty if not all smoke inspections were passed. It was not until 1947 that California authorized the creation of Air Pollution Control Districts in every county of the state.
In botany, apical dominance is the phenomenon whereby the main, central stem of the plant is dominant over (i.e., grows more strongly than) other side stems; on a branch the main stem of the branch is further dominant over its own side twigs. Plant physiology describes apical dominance as the control exerted by the terminal bud (and shoot apex) over the outgrowth of lateral buds.
Sources: en.wikipedia.org
Class A (or 1) (Rhodopsin-like) Class B (or 2) (Secretin receptor family) Class C (or 3) (Metabotropic glutamate/pheromone) Class D (or 4) (Fungal mating pheromone receptors) Class E (or 5) (Cyclic AMP receptors) Class F (or 6) (Frizzled/Smoothened) More recently, an alternative classification system called GRAFS (Glutamate, Rhodopsin, Adhesion, Frizzled/Taste2, Secretin) has been proposed for vertebrate GPCRs. They correspond to classical classes C, A, B2, F, and B. An early study based on available DNA sequence suggested that the human genome encodes roughly 750 G protein-coupled receptors, about 350 of which detect hormones, growth factors, and other endogenous ligands. Approximately 150 of the GPCRs found in the human genome have unknown functions. Some web-servers and bioinformatics prediction methods have been used for predicting the classification of GPCRs according to their amino acid sequence alone, by means of the pseudo amino acid composition approach. GPCRs are involved in a wide variety of physiological processes. Some examples of their physiological roles include:
Arginylglycylaspartic acid (RGD) is the most common peptide motif responsible for cell adhesion to the extracellular matrix (ECM), found in species ranging from Drosophila to humans. Cell adhesion proteins called integrins recognize and bind to this sequence, which is found within many matrix proteins, including fibronectin, fibrinogen, vitronectin, osteopontin, and several other adhesive extracellular matrix proteins. The discovery of RGD and elucidation of how RGD binds to integrins has led to the development of a number of drugs and diagnostics, while the peptide itself is used ubiquitously in bioengineering. Depending on the application and the integrin targeted, RGD can be chemically modified or replaced by a similar peptide which promotes cell adhesion.
A chromogranin A-derived antifungal peptide (CGA 47–66, chromofungin) when embedded on a surface has been shown to have antifungal activity by interacting with the fungal membrane and thereby penetrating the cell. Additionally, in vitro studies have demonstrated that such an antifungal coating can inhibit the growth of yeast Candida albicans by 65% and completely stop the proliferation of filamentous fungus Neurospora crassa. Copper and copper alloy surfaces have demonstrated a die-off of Aspergillus spp., Fusarium spp., Penicillium chrysogenum, Aspergillus niger and Candida albicans fungal spores. Hence, the potential to help prevent the spread of fungi that cause human infections by using copper alloys (instead of non-antifungal metals) in air conditioning systems is worthy of further investigation. The physical topology of a surface will determine the viable environment for bacteria. It may affect a microbe's ability to adhere to its surface. Textile surfaces tend to be very easy for microbes to adhere to due to the abundance of interstitial spacing between fibers.
Anne-Claude Gingras is a senior investigator at Lunenfeld-Tanenbaum Research Institute, and a professor in the department of molecular genetics at the University of Toronto. She is an expert in mass spectrometry based proteomics technology that allows identification and quantification of protein from various biological samples. Gingras was born on Île d'Orléans, Quebec. She earned her undergraduate degree at Université Laval in Quebec. She completed her PhD in biochemistry at McGill University in Montreal, studying how 4E-BP1 regulated translation initiation, under the mentorship of Nahum Sonenberg. After graduating in 2001, she began postdoctoral research in Seattle at the Institute for Systems Biology in the lab of Ruedi Aebersold, where she studied proteomics for three years. In 2005, Gingras moved to Toronto and joined the Lunenfeld-Tanenbaum Research Institute, and in 2006, she began teaching at the University of Toronto in the department of molecular genetics.
AlphaKnot is a scientific database and web server for detecting, classifying, and visualizing protein knots and other forms of protein-chain entanglement. It was developed to facilitate the analysis of protein structures predicted by AlphaFold and other machine-learning methods, but can also be used to analyze experimentally determined structures. The current version, AlphaKnot 2.0, combines two closely related components: a precomputed database containing proteins identified as knotted in large-scale structure-prediction datasets, and an analysis server that allows users to investigate the topology of individual protein structures in greater detail.
Sources: en.wikipedia.org
Liquid chromatography–mass spectrometry is common for identity and purity checks. High-performance liquid chromatography with ultraviolet detection can also be used. Both methods require a suitable reference standard.
The solid is usually kept desiccated at -20 °C or lower and protected from light. Stock solutions are aliquoted to limit freeze–thaw cycles. Aqueous solutions are not generally recommended for long-term storage.
Laws differ by country and by intended use. It is not an approved medicine, and many vendors sell it as a research chemical. Purchasers are responsible for confirming local restrictions.
SR9009 is a synthetic research compound that acts on REV-ERB nuclear receptors. It is not approved for human use and is sold only as a research chemical. Its effects have been studied mainly in cells and rodents.