IntEnz

EC 6.3.4.21 - Nicotinate phosphoribosyltransferase

IntEnz Enzyme Nomenclature
EC 6.3.4.21

Names

Reaction

• 36163 [IUBMB]
  5-phospho-α-D-ribose 1-diphosphate

  5-phospho-alpha-D-ribose 1-diphosphate

  Name origin: UniProt - CHECKED (C)

  CHEBI:58017

  Formula: C5H8O14P3
  Charge: -5

  ChEBI compound status: CHECKED (C)

  

  +

  ATP

  ATP

  Name origin: UniProt - CHECKED (C)

  CHEBI:30616

  Formula: C10H12N5O13P3
  Charge: -4

  ChEBI compound status: CHECKED (C)

  

  +

  H₂O

  H2O

  Name origin: UniProt - CHECKED (C)

  CHEBI:15377

  Formula: H2O
  Charge: 0

  ChEBI compound status: CHECKED (C)

  

  +

  nicotinate

  nicotinate

  Name origin: UniProt - CHECKED (C)

  CHEBI:32544

  Formula: C6H4NO2
  Charge: -1

  ChEBI compound status: CHECKED (C)

  

  =

  ADP

  ADP

  Name origin: UniProt - CHECKED (C)

  CHEBI:456216

  Formula: C10H12N5O10P2
  Charge: -3

  ChEBI compound status: CHECKED (C)

  

  +

  diphosphate

  diphosphate

  Name origin: UniProt - CHECKED (C)

  CHEBI:33019

  Formula: HO7P2
  Charge: -3

  ChEBI compound status: CHECKED (C)

  

  +

  nicotinate β-D-ribonucleotide

  nicotinate beta-D-ribonucleotide

  Name origin: UniProt - CHECKED (C)

  CHEBI:57502

  Formula: C11H12NO9P
  Charge: -2

  ChEBI compound status: CHECKED (C)

  

  +

  phosphate

  phosphate

  Name origin: UniProt - CHECKED (C)

  CHEBI:43474

  Formula: HO4P
  Charge: -2

  ChEBI compound status: CHECKED (C)

  

Comments:

The enzyme, which is involved in pyridine nucleotide recycling, can form β-nicotinate D-ribonucleotide and diphosphate from nicotinate and 5-phospho-α-D-ribose 1-diphosphate (PRPP) in the absence of ATP. However, when ATP is available the enzyme is phosphorylated resulting in a much lower Km for nicotinate. The phospho-enzyme is hydrolysed during the transferase reaction, regenerating the low affinity form. The presence of ATP shifts the products/substrates equilibrium from 0.67 to 1100 [4].

Links to other databases

References

1. Imsande, J.
   Pathway of diphosphopyridine nucleotide biosynthesis in Escherichia coli.
   J. Biol. Chem. 236 : 1494-1497 (1961). [PMID: 13717628]
2. Imsande, J. and Handler, P.
   Biosynthesis of diphosphopyridine nucleotide. III. Nicotinic acid mononucleotide pyrophosphorylase.
   J. Biol. Chem. 236 : 525-530 (1961). [PMID: 13717627]
3. Kosaka, A., Spivey, H.O. and Gholson, R.K.
   Nicotinate phosphoribosyltransferase of yeast. Purification and properties.
   J. Biol. Chem. 246 : 3277-3283 (1971). [PMID: 4324895]
4. Vinitsky, A., Grubmeyer, C.
   A new paradigm for biochemical energy coupling. Salmonella typhimurium nicotinate phosphoribosyltransferase.
   J. Biol. Chem. 268 : 26004-26010 (1993). [PMID: 7503993]

[EC 6.3.4.21 created 1961 as EC 2.4.2.11, transferred 2013 to EC 6.3.4.21]