Dihydrofolate reductase, or DHFR, is an enzyme that reduces dihydrofolic acid to tetrahydrofolic acid, using NADPH as an electron donor, which can be converted to the kinds of tetrahydrofolate cofactors used in 1-carbon transfer chemistry. In humans, the DHFR enzyme is encoded by the DHFR gene. It is found in the q14.1 region of chromosome 5.
Trimethoprim (TMP) is an antibiotic used mainly in the treatment of bladder infections. Other uses include for middle ear infections and travelers' diarrhea. With sulfamethoxazole or dapsone it may be used for Pneumocystis pneumonia in people with HIV/AIDS. It is taken orally.
Folinic acid, also known as leucovorin, is a medication used to decrease the toxic effects of methotrexate and pyrimethamine. It is also used in combination with 5-fluorouracil to treat colorectal cancer and pancreatic cancer, may be used to treat folate deficiency that results in anemia, and methanol poisoning. It is taken by mouth, injection into a muscle, or injection into a vein.
Aminopterin, the 4-amino derivative of folic acid, is an antineoplastic drug with immunosuppressive properties often used in chemotherapy. Aminopterin is a synthetic derivative of pterin. Aminopterin works as an enzyme inhibitor by competing for the folate binding site of the enzyme dihydrofolate reductase. Its binding affinity for dihydrofolate reductase effectively blocks tetrahydrofolate synthesis. This results in the depletion of nucleotide precursors and inhibition of DNA, RNA, and protein synthesis.
Pemetrexed, sold under the brand name Alimta among others, is a chemotherapy medication for the treatment of pleural mesothelioma and non-small cell lung cancer (NSCLC)..
An antimetabolite is a chemical that inhibits the use of a metabolite, which is another chemical that is part of normal metabolism. Such substances are often similar in structure to the metabolite that they interfere with, such as the antifolates that interfere with the use of folic acid; thus, competitive inhibition can occur, and the presence of antimetabolites can have toxic effects on cells, such as halting cell growth and cell division, so these compounds are used in chemotherapy for cancer.
A corrole is an aromatic tetrapyrrole. The corrin ring is also present in cobalamin (vitamin B12). The ring consists of nineteen carbon atoms, with four nitrogen atoms in the core of the molecule. In this sense, corrole is very similar to porphyrin.
A photoswitch is a type of molecule that can change its structural geometry and chemical properties upon irradiation with electromagnetic radiation. Although often used interchangeably with the term molecular machine, a switch does not perform work upon a change in its shape whereas a machine does. However, photochromic compounds are the necessary building blocks for light driven molecular motors and machines. Upon irradiation with light, photoisomerization about double bonds in the molecule can lead to changes in the cis- or trans- configuration. These photochromic molecules are being considered for a range of applications.
In genetics, crosslinking of DNA occurs when various exogenous or endogenous agents react with two nucleotides of DNA, forming a covalent linkage between them. This crosslink can occur within the same strand (intrastrand) or between opposite strands of double-stranded DNA (interstrand). These adducts interfere with cellular metabolism, such as DNA replication and transcription, triggering cell death. These crosslinks can, however, be repaired through excision or recombination pathways.
Dihydrofolic acid (conjugate base dihydrofolate) (DHF) is a folic acid (vitamin B9) derivative which is converted to tetrahydrofolic acid by dihydrofolate reductase. Since tetrahydrofolate is needed to make both purines and pyrimidines, which are building blocks of DNA and RNA, dihydrofolate reductase is targeted by various drugs to prevent nucleic acid synthesis.
Cycloguanil is a dihydrofolate reductase inhibitor, and is a metabolite of the antimalarial drug proguanil; its formation in vivo has been thought to be primarily responsible for the antimalarial activity of proguanil. However, more recent work has indicated that, while proguanil is synergistic with the drug atovaquone, cycloguanil is in fact antagonistic to the effects of atovaquone, suggesting that, unlike cycloguanil, proguanil may have an alternative mechanism of antimalarial action besides dihydrofolate reductase inhibition.
Antifolates are a class of antimetabolite medications that antagonise (that is, block) the actions of folic acid (vitamin B9). Folic acid's primary function in the body is as a cofactor to various methyltransferases involved in serine, methionine, thymidine and purine biosynthesis. Consequently, antifolates inhibit cell division, DNA/RNA synthesis and repair and protein synthesis. Some such as proguanil, pyrimethamine and trimethoprim selectively inhibit folate's actions in microbial organisms such as bacteria, protozoa and fungi. The majority of antifolates work by inhibiting dihydrofolate reductase (DHFR).
Bruce D. Roth is an American organic and medicinal chemist who trained at Iowa State University and the University of Rochester, and, at the age of 32, discovered atorvastatin, the statin-class drug sold as Lipitor that would become the largest-selling drug in pharmaceutical history. His honours include being named a 2008 Hero of Chemistry by the American Chemical Society, and being chosen as the Perkin Medal awardee, the highest honour given in the U.S. chemical industry, by the Society of Chemical Industry, American section in 2013.
A dihydrofolate reductase inhibitor is a molecule that inhibits the function of dihydrofolate reductase, and is a type of antifolate.
Stephen James Benkovic is an American chemist known for his contributions to the field of enzymology. He holds the Evan Pugh University Professorship and Eberly Chair in Chemistry at The Pennsylvania State University. He has developed boron compounds that are active pharmacophores against a variety of diseases. Benkovic has concentrated on the assembly and kinetic attributes of the enzymatic machinery that performs DNA replication, DNA repair, and purine biosynthesis.
Quasi-crystals are supramolecular aggregates exhibiting both crystalline (solid) properties as well as amorphous, liquid-like properties.
Photostatins are inhibitors that can be switched on and off in vivo by visible light, to optically control microtubule dynamics. Photostatins are a form of photopharmacology.
Dirk Trauner is an Austrian chemist.
Photopharmacology, an emerging approach in medicine, involves activating and deactivating photoswitchable molecules with light for target drug delivery. Clinicians use the energy of light to change the shape and chemical properties of a drug, resulting in different biological activity. This is done to ultimately achieve control of when and where drugs are active in a reversible manner, and to prevent side effects and exposure to the environment of antibiotics. Switching drugs "on" and "off" is achieved by introducing photoswitches such as azobenzene, spiropyran or diarylethene into the drug. Photopharmalogical drugs with a photoswitch have two different states, which light can toggle between. Since both states have a different structure, the activity of the drug is different, hence the "on" and "off" state of the drug. An example is photostatin, which is an inhibitor that can be switched on and off in vivo to optically control microtubule dynamics.
