PPX1/YHR201C Summary Help

Standard Name PPX1
Systematic Name YHR201C
Feature Type ORF, Verified
Description Exopolyphosphatase; hydrolyzes inorganic polyphosphate (poly P) into Pi residues; located in the cytosol, plasma membrane, and mitochondrial matrix (1, 2, 3 and see Summary Paragraph)
Chromosomal Location
ChrVIII:501143 to 499950 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Gene Ontology Annotations All PPX1 GO evidence and references
  View Computational GO annotations for PPX1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 1 genes
Classical genetics
Large-scale survey
13 total interaction(s) for 13 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 3
  • Affinity Capture-RNA: 1
  • Biochemical Activity: 1

Genetic Interactions
  • Negative Genetic: 6
  • Phenotypic Enhancement: 1
  • Positive Genetic: 1

Expression Summary
Length (a.a.) 397
Molecular Weight (Da) 45,051
Isoelectric Point (pI) 5.48
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrVIII:501143 to 499950 | ORF Map | GBrowse
Note: this feature is encoded on the Crick strand.
Last Update Coordinates: 2005-11-07 | Sequence: 1996-07-31
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..1194 501143..499950 2005-11-07 1996-07-31
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | E.C. | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000001244

PPX1 was the first gene related to inorganic polyphosphate (poly P) metabolism isolated from a eukaryotic cell (1). Poly P is a chain of tens or many hundreds of phosphate (Pi) residues linked by high-energy phosphoanhydride bonds. PPX1 encodes a potent cytoplasmic exopolyphosphatase, responsible for hydrolyzing poly P into Pi residues (2). The enzyme acts as an exoenzyme in a processive mode releasing Pi residues from the ends of poly P chain (2). The enzyme is a monomer with a molecular mass of 40 kDa (2). For optimal activity the enzyme depends on divalent metal ions, which may bind the enzyme in addition to chelating the poly P chain (2). The yeast Ppx1p is much more active than its E. coli counterpart and acts on substrate poly P chains of a broader size range (i.e., 3 to 1000 residues). It does not act on pyrophosphate, ATP, or the cyclic form of tripolyphosphate (2). Mutants lacking Ppx1p have normal growth phenotype (2); several other polyphosphatases are known in yeast which might replace its function (4, 5).

Last updated: 2001-11-15 Contact SGD

References cited on this page View Complete Literature Guide for PPX1
1) Wurst H, et al.  (1995) The gene for a major exopolyphosphatase of Saccharomyces cerevisiae. J Bacteriol 177(4):898-906
2) Wurst H and Kornberg A  (1994) A soluble exopolyphosphatase of Saccharomyces cerevisiae. Purification and characterization. J Biol Chem 269(15):10996-1001
3) Lichko LP, et al.  (2003) Exopolyphosphatases of the yeast Saccharomyces cerevisiae. FEMS Yeast Res 3(3):233-8
4) Andreeva N, et al.  (1998) Purification and properties of polyphosphatase from Saccharomyces cerevisiae cytosol. Yeast 14(4):383-90
5) Sethuraman A, et al.  (2001) The endopolyphosphatase gene: essential in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A 98(15):8542-7