Cloned (Comment) | Organism |
---|---|
recombinant expression of GST-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3) pLysS | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
K132N | site-directed mutagenesis, the mutant shows no conformational or kinetic defect, no loss in relative activity (97% of wild-type activity) at standard conditions nor change in Vmax and Km. The mutation is not associated to acute intermittent porphyria, AIP | Homo sapiens |
R116W | site-directed mutagenesis, the mutant shows 0.5% of wild-type activity and defects in conformational stability. The mutation is associated to acute intermittent porphyria, AIP | Homo sapiens |
R167W | site-directed mutagenesis, the mutant shows 4.2% of wild-type activity and defects in enzyme kinetics associated with a very high Km and decreased Vmax. The mutation is associated to acute intermittent porphyria, AIP | Homo sapiens |
R173W | site-directed mutagenesis, the mutant shows 0.6% of wild-type activity and defects in conformational stability and in enzyme kinetics. The mutation is associated to acute intermittent porphyria, AIP | Homo sapiens |
V215E | site-directed mutagenesis, the mutant shows 30% of wild-type activity and lower conformational stability and probably a perturbed elongation process, also 70% loss in both activity and Vmax. The mutation is associated to acute intermittent porphyria, AIP | Homo sapiens |
General Stability | Organism |
---|---|
DTT stabilizes | Homo sapiens |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetics for uroporphyrinogen formation | Homo sapiens | |
0.039 | - |
porphobilinogen | recombinant mutant V215E, pH 8.2, 37°C | Homo sapiens | |
0.041 | - |
porphobilinogen | recombinant mutant K132N, pH 8.2, 37°C | Homo sapiens | |
0.048 | - |
porphobilinogen | recombinant wild-type enzyme, pH 8.2, 37°C | Homo sapiens | |
1.579 | - |
porphobilinogen | recombinant mutant R167W, pH 8.2, 37°C | Homo sapiens |
Molecular Weight [Da] | Molecular Weight Maximum [Da] | Comment | Organism |
---|---|---|---|
44000 | - |
- |
Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
4 porphobilinogen + H2O | Homo sapiens | - |
hydroxymethylbilane + 4 NH3 | - |
? | |
additional information | Homo sapiens | the enzyme is also active in uroporphyrinogen formation from porphobilinogen, cf. EC 4.2.1.75 | ? | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | P08397 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant GST-tagged wild-type and mutant enzymes from Escherichia coli strain BL21(DE3) pLysS by glutathione affinity chromatgraphy, tag cleavage by thrombin, and ultrafiltration | Homo sapiens |
Specific Activity Minimum [µmol/min/mg] | Specific Activity Maximum [µmol/min/mg] | Comment | Organism |
---|---|---|---|
additional information | - |
activity determinatin by uroporphyrinogen formation measurement | Homo sapiens |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
4 porphobilinogen + H2O | - |
Homo sapiens | hydroxymethylbilane + 4 NH3 | - |
? | |
additional information | the enzyme is also active in uroporphyrinogen formation from porphobilinogen, cf. EC 4.2.1.75 | Homo sapiens | ? | - |
? | |
additional information | enzyme-intermediates with increasing number of porphobilinogen molecules are formed during the catalysis of enzyme HMBS | Homo sapiens | ? | - |
? |
Subunits | Comment | Organism |
---|---|---|
? | x * 44000, about, recombinant detagged wild-type and mutant enzymes, SDS-PAGE | Homo sapiens |
Synonyms | Comment | Organism |
---|---|---|
HMBS | - |
Homo sapiens |
PBG deaminase | - |
Homo sapiens |
porphobilinogen deaminase | - |
Homo sapiens |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
Temperature Stability Minimum [°C] | Temperature Stability Maximum [°C] | Comment | Organism |
---|---|---|---|
additional information | - |
the thermostability of the enzyme increases when the dipyrromethane cofactor binds to the apoenzyme and the holoenzyme is formed. A decrease in thermal stability is measured concomitant to elongation of the pyrrole chain, indicating a loosening of the structure prior to product release | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8.2 | - |
assay at | Homo sapiens |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
dipyrromethane | - |
Homo sapiens |
General Information | Comment | Organism |
---|---|---|
malfunction | autosomal dominantly inherited disease acute intermittent porphyria, AIP, is caused by mutations in hydroxymethylbilane synthase, phenotypes, overview | Homo sapiens |
metabolism | hydroxymethylbilane synthase is the third enzyme in the heme biosynthesis pathway | Homo sapiens |