Information on EC 2.4.99.20 - 2'-phospho-ADP-ribosyl cyclase/2'-phospho-cyclic-ADP-ribose transferase and Organism(s) Homo sapiens and UniProt Accession P28907

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Homo sapiens
UNIPROT: P28907


The taxonomic range for the selected organisms is: Homo sapiens

The enzyme appears in selected viruses and cellular organisms

EC NUMBER
COMMENTARY hide
2.4.99.20
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RECOMMENDED NAME
GeneOntology No.
2'-phospho-ADP-ribosyl cyclase/2'-phospho-cyclic-ADP-ribose transferase
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PATHWAY
BRENDA Link
KEGG Link
MetaCyc Link
Nicotinate and nicotinamide metabolism
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SYSTEMATIC NAME
IUBMB Comments
NADP+:nicotinate ADP-ribosyltransferase
This multiunctional enzyme catalyses both the removal of nicotinamide from NADP+, forming 2'-phospho-cyclic ADP-ribose, and the addition of nicotinate to the cyclic product, forming NAADP+, a calcium messenger that can mobilize intracellular Ca2+ stores and activate Ca2+ influx to regulate a wide range of physiological processes. In addition, the enzyme also catalyses EC 3.2.2.6, ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase.
ORGANISM
COMMENTARY hide
LITERATURE
UNIPROT
SEQUENCE DB
SOURCE
GENERAL INFORMATION
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
physiological function
gene silencing of CD38 does not inhibit NAADP synthesis in intact Jurkat T cells. In vitro, both NAADP formation by base-exchange and degradation to 2-phospho adenosine diphosphoribose are efficiently decreased. Thus in vivo CD38 appears to be a NAADP degrading rather than a NAADP forming enzyme
SUBSTRATE
PRODUCT                       
REACTION DIAGRAM
ORGANISM
UNIPROT
COMMENTARY
(Substrate) hide
LITERATURE
(Substrate)
COMMENTARY
(Product) hide
LITERATURE
(Product)
Reversibility
r=reversible
ir=irreversible
?=not specified
2'-phospho-cyclic ADP-ribose + nicotinate
nicotinate-adenine dinucleotide phosphate
show the reaction diagram
NADP+
2'-phospho-cyclic ADP-ribose + nicotinamide
show the reaction diagram
NGDP+
2'-phospho-cyclic GDP-ribose + nicotinamide
show the reaction diagram
enzyme cyclizes nicotinamide guanine dinucleotide to produce a fluorescent product, cyclic GDP-ribose, which has a site of cyclization different from cADPR
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?
additional information
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KM VALUE [mM]
SUBSTRATE
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
IMAGE
5
nicotinate
pH 5, 22°C
Crystallization/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
complex of isoform CD38 with substrate NMN shows that the nicotinamide moiety is in close contact with Glu146 at 3.27 A and Asp155 at 2.52 A. Residue Asp147 is situated and directed away from the bound substrate
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Cloned/COMMENTARY
ORGANISM
UNIPROT
LITERATURE
ENGINEERING
ORGANISM
UNIPROT
COMMENTARY hide
LITERATURE
D147V
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mutation has minimal effects on pH-dependence of the enzyme
D155N
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mutation eliminates the strong pH dependence of the catalyzed reactions
D155Q
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mutation eliminates the strong pH dependence of the catalyzed reactions; mutation preserves the strong pH dependence of the catalyzed reactions
E146A
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mutation eliminates the strong pH dependence of the catalyzed reactions
E146G
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mutation eliminates the strong pH dependence of the catalyzed reactions