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Literature summary for 2.5.1.61 extracted from

  • Bustad, H.; Vorland, M.; Roenneseth, E.; Sandberg, S.; Martinez, A.; Toska, K.
    Conformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyria (2013), Biosci. Rep., 33, 617-626.
    View publication on PubMedView publication on EuropePMC
Search for more literature for 2.5.1.61

Cloned(Commentary)

Cloned (Comment) Organism
recombinant expression of GST-tagged wild-type and mutant enzymes in Escherichia coli strain BL21(DE3) pLysS Homo sapiens

Protein Variants

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

General Stability Organism
DTT stabilizes Homo sapiens

KM Value [mM]

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 [Da] Molecular Weight Maximum [Da] Comment Organism
44000
-
-
 Homo sapiens

Natural Substrates/ Products (Substrates)

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

Organism UniProt Comment Textmining
Homo sapiens P08397
-
-

Purification (Commentary)

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 [micromol/min/mg]

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 and Products (Substrate)

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

Subunits Comment Organism
? x * 44000, about, recombinant detagged wild-type and mutant enzymes, SDS-PAGE Homo sapiens

Synonyms

Synonyms Comment Organism
HMBS
-
 Homo sapiens
PBG deaminase
-
 Homo sapiens
porphobilinogen deaminase
-
 Homo sapiens

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
 assay at Homo sapiens

Temperature Stability [°C]

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

pH Optimum Minimum pH Optimum Maximum Comment Organism
8.2
-
 assay at Homo sapiens

Cofactor

Cofactor Comment Organism Structure
dipyrromethane
-
 Homo sapiens

General Information

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