Nucleotide salvage

A salvage pathway is a pathway in which nucleotides (purine and pyrimidine) are synthesized from intermediates in the degradative pathway for nucleotides.

Salvage pathways are used to recover bases and nucleosides that are formed during degradation of RNA and DNA. This is important in some organs because some tissues cannot undergo de novo synthesis.

The salvaged bases and nucleosides can then be converted back into nucleotides.

Contents

Substrates

The salvage pathway requires distinct substrates:

Pyrimidines

Uridine phosphorylase adds ribose-1-phospate to the free base uracil, forming uridine monophosphate. Uridine kinase then phosphorylates this nucleoside into its diphosphate and triphosphate forms. Deoxythymidine phosphorylase adds deoxyribose-1-phosphate to thymine, forming deoxythymidine monophosphate. Thymidine kinase can then phosphorylate this compound to deoxythymidine diphosphate and triphosphate.

The salvage of pyrimidine ribonucleotides.


Purines

Phosphoribosyltransferases add activated ribose-5-phosphate (called phosphoribosyl pyrophosphate or PRPP) to bases, creating nucleotide monophosphates. There are two types of phosphoribosyltransferases: adenosine phosphoribosyltransferase (APRT) and hypoxanthine-guanine phosphoribosyltransferase (HGPRT). Lesch-Nyhan syndrome is associated with a deficiency of HGPRT.

Nucleoside Enzyme Nucleotide
hypoxanthine hypoxanthine/guanine phosphoribosyl transferase (HGPRT) IMP
guanine hypoxanthine/guanine phosphoribosyl transferase (HGPRT) GMP
adenine adenine phosphoribosyltransferase (APRT) AMP

External links


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Nucleotide — Nucleotides are molecules that, when joined together, make up the structural units of RNA and DNA. In addition, nucleotides participate in cellular signaling (cGMP and cAMP), and are incorporated into important cofactors of enzymatic reactions… …   Wikipedia

  • Metabolism — Cell metabolism redirects here. For the journal, see Cell Metabolism. Structure of adenosine triphosphate, a central intermediate in energy metabolism Metabolism (from Greek: μεταβολή metabolē , change or Greek: μεταβολισμός metabolismos,… …   Wikipedia

  • Purine nucleoside phosphorylase — Not to be confused with polynucleotide phosphorylase. purine nucleoside phosphorylase Identifiers EC number 2.4.2.1 CAS number …   Wikipedia

  • Lesch–Nyhan syndrome — Lesch Nyhan syndrome Classification and external resources ICD 10 E79.1 ICD 9 277.2 …   Wikipedia

  • AMP deaminase — Adenosine monophosphate deaminase 1 Identifiers Symbols AMPD1; MAD; MADA External IDs …   Wikipedia

  • Nucleoside phosphorylase — Nucleoside phosphorylase, also known as NP, is a human gene.cite web | title = Entrez Gene: NP nucleoside phosphorylase| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene Cmd=ShowDetailView TermToSearch=4860| accessdate = ] PBB Summary… …   Wikipedia

  • Hypoxanthine-guanine phosphoribosyltransferase — (HPRTcite web |url=http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene cmd=retrieve dopt=default list uids=3251 rn=1 |title=Entrez Gene: hypoxanthine phosphoribosyltransferase 1 (Lesch Nyhan syndrome)] ) is an enzyme in purine metabolism. PBB… …   Wikipedia

  • CTP synthase — Cytidine triphosphate Identifiers EC number 6.3.4.2 …   Wikipedia

  • Uridine monophosphate synthetase — PDB rendering based on 2eaw …   Wikipedia

  • Dihydrofolate reductase — Ribbon diagram of human dihydrofolate reductase in complex with folate (blue). From PDB 1DRF …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.