Pyrimidine

From Academic Kids


Pyrimidine
Chemical namePyrimidine
Chemical formulaC4H4N2
Molecular mass80.09 g/mol
Density1.016 g/ml
Melting point20 - 22 C
Boiling point123 - 124 C
CAS number289-95-2
SMILESC1=NC=NC=C1
Missing image
Pyrimidine_chemical_structure.png
Chemical structure of pyrimidine


Pyrimidine is a heterocyclic aromatic organic compound, which is similar to benzene and pyridine and that contains two nitrogen atoms at positions 1 and 3 of the six-membered ring.

Three nucleobases found in nucleic acids, namely cytosine, thymine, and uracil, are pyrimidine derivatives. In DNA and RNA, these bases form hydrogen bonds with their complementary purines.

purine  pyrimidine
   A         T
   G         C

In RNA, the complement of A is U instead of T:

purine  pyrimidine
   A         U
   G         C
Missing image
Thymine_chemical_structure.png
Chemical structure of thymine

Missing image
Uracil_chemical_structure.png
Chemical structure of uracil

Missing image
Cytosine_chemical_structure.png
Chemical structure of cytosine

Thymine Uracil Cytosine

These hydrogen bonding modes are for classical Watson-Crick base pairing. Other hydrogen bonding modes 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.

Contents

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 broken down completely to CO2. H2O and urea. Cytosine can be broken down to uracil which can be further broken down to N-carbaomyl-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

  • Lancaster (http://www.lancastersynthesis.com/homecatsearch.htm) (now part of Alfa)
  • Fisher (https://www1.fishersci.com/index.jsp)
  • VWR (http://www.vwr.com/index.htm)
  • Alfa (http://www.alfa.com/alf/index.htm)
  • Aldrich (http://www.sigmaaldrich.com)
  • Aurora Fine Chemicals (http://www.aurora-feinchemie.com)

See also

Template:Biochem-stubca:Pirimidina de:Pyrimidin es:pirimidina fr:Pyrimidine ja:ピリミジン nl:pyrimidine pl:pirymidyna ru:Пиримидин

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