UniProt functional annotation for P0C0H6

UniProt code: P0C0H6.

Organism: Streptococcus pyogenes.
Taxonomy: Bacteria; Firmicutes; Bacilli; Lactobacillales; Streptococcaceae; Streptococcus.
 
Function: Catalyzes the conversion of inosine 5'-phosphate (IMP) to xanthosine 5'-phosphate (XMP), the first committed and rate-limiting step in the de novo synthesis of guanine nucleotides, and therefore plays an important role in the regulation of cell growth. {ECO:0000255|HAMAP-Rule:MF_01964}.
 
Catalytic activity: Reaction=H2O + IMP + NAD(+) = H(+) + NADH + XMP; Xref=Rhea:RHEA:11708, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:57464, ChEBI:CHEBI:57540, ChEBI:CHEBI:57945, ChEBI:CHEBI:58053; EC=1.1.1.205; Evidence={ECO:0000255|HAMAP-Rule:MF_01964};
Cofactor: Name=K(+); Xref=ChEBI:CHEBI:29103; Evidence={ECO:0000255|HAMAP-Rule:MF_01964};
Activity regulation: Mycophenolic acid (MPA) is a non-competitive inhibitor that prevents formation of the closed enzyme conformation by binding to the same site as the amobile flap. In contrast, mizoribine monophosphate (MZP) is a competitive inhibitor that induces the closed conformation. MPA is a potent inhibitor of mammalian IMPDHs but a poor inhibitor of the bacterial enzymes. MZP is a more potent inhibitor of bacterial IMPDH. {ECO:0000255|HAMAP-Rule:MF_01964}.
Biophysicochemical properties: Kinetic parameters: KM=62 uM for Inosine 5'-phosphate {ECO:0000269|PubMed:10200156}; KM=1180 uM for NAD(+) {ECO:0000269|PubMed:10200156}; pH dependence: Optimum pH is 7.8. {ECO:0000269|PubMed:10200156};
Pathway: Purine metabolism; XMP biosynthesis via de novo pathway; XMP from IMP: step 1/1. {ECO:0000255|HAMAP-Rule:MF_01964}.
Subunit: Homotetramer. {ECO:0000255|HAMAP-Rule:MF_01964, ECO:0000269|PubMed:10200156}.
Mass spectrometry: Mass=52328; Method=MALDI; Evidence={ECO:0000269|PubMed:10200156};
Similarity: Belongs to the IMPDH/GMPR family. {ECO:0000255|HAMAP- Rule:MF_01964}.

Annotations taken from UniProtKB at the EBI.