Q97U27 · GAD_SACS2
- ProteinD-gluconate/D-galactonate dehydratase
- Genegad
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids395 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Involved in the degradation of glucose and galactose via the branched variant of the Entner-Doudoroff pathway. Catalyzes the dehydration of gluconate to produce 2-keto-3-deoxygluconate (KDG). It is also able to catalyze the dehydration of galactonate to produce 2-keto-3-deoxygalactonate (KDGal).
Miscellaneous
D-gluconate dehydratase activity is lost after incubation with phosphatase, whereas no such decrease in activity is observed when the enzymes are incubated in the same reaction mixtures without phosphatase. Analysis of the amino acid sequence of D-gluconate dehydratase indicate the presence of several putative phosphorylation sites on serine, threonine and tyrosine residues.
Catalytic activity
- D-gluconate = 2-dehydro-3-deoxy-D-gluconate + H2O
- D-gluconate = 2-dehydro-3-deoxy-D-gluconate + H2O
Cofactor
Co2+ (UniProtKB | Rhea| CHEBI:48828 )
Mn2+ (UniProtKB | Rhea| CHEBI:29035 )
Ni2+ (UniProtKB | Rhea| CHEBI:49786 )
Note: Binds 1 Mg2+ ion per subunit. Can also use divalent metal ions such as Co2+, Mn2+ and Ni2+.
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
0.45 mM | gluconate | 7 | 78 | |||
0.81 mM | galactonate | 6 | 70 | |||
1.57 mM | gluconate | 6 | 70 |
Vmax | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|
0.15 μmol/min/mg | 7 | 78 | with gluconate as substrate |
kcat is 10.4 sec-1 for gluconate and 1.08 sec-1 for galactonate (at 70 degrees Celsius and pH 6). kcat is 12.6 sec-1 for gluconate (at 78 degrees Celsius and pH 7).
pH Dependence
Optimum pH is between 6.5 and 7.5.
Temperature Dependence
Optimum temperature is between 80 and 100 degrees Celsius. At 80 degrees Celsius, the dehydratase is stable for over 2 hours, but at 90 degrees Celsius its activity is decreased to less than 50% in 2 hours and its half-life diminishes to 120 minutes. At 100 degrees Celsius, the enzyme has a half-life of less than 40 minutes. The activity is almost undetectable below 60 degrees Celsius.
Pathway
Carbohydrate acid metabolism; D-gluconate degradation.
Features
Showing features for binding site, active site, site.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Binding site | 197 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Active site | 199 | Proton donor | ||||
Sequence: H | ||||||
Binding site | 223 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Binding site | 249 | Mg2+ (UniProtKB | ChEBI) | ||||
Sequence: E | ||||||
Site | 272 | Increases basicity of active site His | ||||
Sequence: D | ||||||
Active site | 299 | Proton acceptor | ||||
Sequence: H | ||||||
Site | 324 | Transition state stabilizer | ||||
Sequence: E |
GO annotations
Aspect | Term | |
---|---|---|
Molecular Function | galactonate dehydratase activity | |
Molecular Function | gluconate dehydratase activity | |
Molecular Function | metal ion binding | |
Biological Process | D-gluconate catabolic process |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameD-gluconate/D-galactonate dehydratase
- EC number
- Short namesGAD ; GNAD
Gene names
Organism names
- Strain
- Taxonomic lineageArchaea > Thermoproteota > Thermoprotei > Sulfolobales > Sulfolobaceae > Saccharolobus
Accessions
- Primary accessionQ97U27
Proteomes
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000422650 | 1-395 | D-gluconate/D-galactonate dehydratase | |||
Sequence: MRIREIEPIVLTSKEKGSATWASIMIVTRVITENGEVGYGEAVPTLRVISVYNAIKQVSKAYIGKEVEEVEKNYHEWYKQDFYLARSFESATAVSAIDIASWDIIGKELGAPIHKLLGGKTRDRVPVYANGWYQDCVTPEEFAEKAKDVVKMGYKALKFDPFGPYYDWIDERGLREAEERVKAVREAVGDNVDILIEHHGRFNANSAIMIAKRLEKYNPGFMEEPVHHEDVIGLRKYKASTHLRVALGERLISEKETAFYVEEGLVNILQPDLTNIGGVTVGRSVIKIAEANDVEVAFHNAFGSIQNAVEIQLSAVTQNLYLLENFYDWFPQWKRDLVYNETPVEGGHVKVPYKPGLGVSINEKIIEQLRAEPIPLDVIEEPVWVVKGTWKNYGV |
Proteomic databases
Interaction
Structure
Family & Domains
Sequence similarities
Belongs to the mandelate racemase/muconate lactonizing enzyme family. GaD subfamily.
Phylogenomic databases
Family and domain databases
Sequence
- Sequence statusComplete
- Length395
- Mass (Da)44,729
- Last updated2001-10-01 v1
- ChecksumBA53EFD93F90A44D
Keywords
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AE006641 EMBL· GenBank· DDBJ | AAK43295.1 EMBL· GenBank· DDBJ | Genomic DNA |