Search results
Results From The WOW.Com Content Network
RNA is composed of pyrimidine and purine nucleotides, both of which are necessary for reliable information transfer, and thus natural selection and Darwinian evolution. Becker et al. showed how pyrimidine nucleosides can be synthesized from small molecules and ribose , driven solely by wet-dry cycles.
Pyrimidine (C 4 H 4 N 2; / p ɪ ˈ r ɪ. m ɪ ˌ d iː n, p aɪ ˈ r ɪ. m ɪ ˌ d iː n /) is an aromatic, heterocyclic, organic compound similar to pyridine (C 5 H 5 N). [3] One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring.
In order to perform these essential cellular processes, both purines and pyrimidines are needed by the cell, and in similar quantities. Both purine and pyrimidine are self-inhibiting and activating. When purines are formed, they inhibit the enzymes required for more purine formation. This self-inhibition occurs as they also activate the enzymes ...
Mycophenolate mofetil is an immunosuppressant drug used to prevent rejection in organ transplantation; it inhibits purine synthesis by blocking inosine monophosphate dehydrogenase (IMPDH). [5] Methotrexate also indirectly inhibits purine synthesis by blocking the metabolism of folic acid (it is an inhibitor of the dihydrofolate reductase).
Pyrimidine, like polycyclic aromatic hydrocarbons (PAHs), a carbon-rich chemical found in the Universe, may have been formed in red giants or in interstellar dust and gas clouds. [ 20 ] Based on 12 C/ 13 C isotopic ratios of organic compounds found in the Murchison meteorite , it is believed that uracil, xanthine , and related molecules can ...
Fluoropyrimidines are a general class organic compounds in which the substituent(s) around a pyrimidine ring include at least one fluorine atom. The term "fluoropyrimidines" is often used more specifically to refer to the subset of this class that are antimetabolites and are used as anticancer medications, which include: Capecitabine; Carmofur ...
Pyrimidine dimers encompass several types, each with distinct structures and implications for DNA integrity. [ citation needed ] Cyclobutane pyrimidine dimer (CPD) is a dimer which features a four-membered ring formed by the fusion of two double-bonded carbons from adjacent pyrimidines.
Pyrazine is less basic than pyridine, pyridazine and pyrimidine. It is a "deliquescent crystal or wax-like solid with a pungent, sweet, corn-like, nutty odour". [3] Pyrazine and a variety of alkylpyrazines are flavor and aroma compounds found in baked and roasted goods.