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EC 2.4.2.11 Details
EC number
2.4.2.11
Accepted name
nicotinate phosphoribosyltransferase
Reaction
nicotinate + 5-phospho-α-D-ribose 1-diphosphate + ATP + H2O = β-nicotinate D-ribonucleotide + diphosphate + ADP + phosphate (overall reaction);;(1a) nicotinate + 5-phospho-α-D-ribose 1-diphosphate = β-nicotinate D-ribonucleotide + diphosphate;;(1b) ATP + H2O = ADP + phosphate
Other name(s)
niacin ribonucleotidase, nicotinic acid mononucleotide glycohydrolase, nicotinic acid mononucleotide pyrophosphorylase, nicotinic acid phosphoribosyltransferase, nicotinate-nucleotide:diphosphate phospho-α-D-ribosyltransferase
Systematic name
β-nicotinate-D-ribonucleotide:diphosphate phospho-α-D-ribosyltransferase
CAS registry number
9030-26-6
Comment
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 hydrolyses it and utilizes the energy to drive the reaction from a products/substrates ratio of 0.67 to a value of 1100 [4]. In addition, the Km values for nicotinate and PRPP decrease by 200-fold when ATP is present.
History
created 1961, deleted 2013
EC Tree
2.4.2.13 created 1961, deleted 1965