Information AboutPyrimidine |
| CATEGORIES ABOUT PYRIMIDINE | |
| nitrogen heterocycles | |
| simple aromatic rings | |
| biomolecules | |
| pyrimidines | |
| SHOPPER'S DELIGHT | |
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Pyrimidine is a Heterocyclic Aromatic Organic Compound similar to Benzene and Pyridine , containing two Nitrogen Atoms at positions 1 and 3 of the six-member ring. It is Isomer ic with two other forms of Diazine . Three Nucleobase s found in Nucleic Acid s, namely Cytosine , Thymine , and Uracil , are pyrimidine derivatives. In DNA and RNA , these bases form Hydrogen Bond s with their Complementary Purine s. purine pyrimidine A T G C In RNA , the complement of A is U instead of T: purine pyrimidine A U G C These hydrogen bonding modes are for classical Watson-Crick Base Pair ing. Other hydrogen bonding modes ("wobble pairings") are available in both DNA and RNA , although the additional 2'-hydroxyl group of RNA expands the configurations through which RNA can form hydrogen bonds. PYRIMIDINE BIOSYNTHESIS Pyrimidine de novo biosynthesis Unlike purines, pyrimidines are assembled before being attached to 5-phosphoribosyl-1-pyrophosphate (PRPP). The first step begins with formation of carbamoyl phosphate by carbamoyl phosphate synthetase II. The second major step is the creation carbamoyl aspartic acid formed by aspartic transcarbamolyase. Once orotic acid is eventually formed from carbamoyl aspartic acid, it is combined with PRPP to form uridine-3'-phosphate (UMP). UMP is then phosphorylated twice to form ribose-PPP-Uridine-5'-triphosphate (UTP). Cytidino-5'-triphosphate (CTP) is formed from UTP utilizing glutamine. Pyrmidine catabolism Pyrimidines are ultimately Catabolized (degraded) to CO2 , H2O , and Urea . Cytosine can be broken down to uracil which can be further broken down to N-carbamoyl-β-alanine. Thymine is broken down into β-aminoisobutyrate which can be further broken down into intermediates eventually leading into the Citric Acid Cycle . β-aminoisobutyrate acts as a rough indicator for rate of DNA turnover. SUPPLIERS/MANUFACTURERS SEE ALSO
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