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Literature summary extracted from

  • Munagala, N.R.; Wang, C.C.
    Altering the purine specificity of hypoxanthine-guanine-xanthine phosphoribosyltransferase from Tritrichomonas foetus by structure-based point mutations in the enzyme protein (1998), Biochemistry, 37, 16612-16619.
    View publication on PubMed

Application

EC Number Application Comment Organism
2.4.2.8 medicine target for anti-trichomonial therapy Tritrichomonas suis

Cloned(Commentary)

EC Number Cloned (Comment) Organism
2.4.2.8 functional expression of wild-type enzyme and mutants in an enzyme-deficient Escherichia coli strain Tritrichomonas suis

Protein Variants

EC Number Protein Variants Comment Organism
2.4.2.8 D163E site directed mutagenesis, slightly changed substrate affinities compared to wild-type Tritrichomonas suis
2.4.2.8 D163N site-directed mutagensis, exchange of xanthine binding residue, loss of the binding ability and activity against xanthine and XMP Tritrichomonas suis
2.4.2.8 F162L site directed mutagenesis, no effect on purine base specificity Tritrichomonas suis
2.4.2.8 I104G site directed mutagenesis, increased Km values for hypoxanthine, guanine, and xanthine Tritrichomonas suis
2.4.2.8 K134Q site directed mutagenesis, mutant recognizes adenine as substrate in addition, but less efficient than mutant K134S Tritrichomonas suis
2.4.2.8 K134S site directed mutagenesis, mutant recognizes adenine as substrate in addition, increased Km values for hypoxanthine, guanine, and xanthine Tritrichomonas suis
2.4.2.8 R155E site directed mutagenesis, reduced affinity to GMP and XMP, catalysation of the forward reaction with guanine and xanthine at accelerated rates, 15fold increased Km for xanthine Tritrichomonas suis
2.4.2.8 R155K site directed mutagenesis, reduced affinity to GMP and XMP, catalysation of the forward reaction with guanine and xanthine at accelerated rates, insensitive to phenylglyoxal Tritrichomonas suis
2.4.2.8 Y156F site directed mutagenesis, weakened binding of GMP and XMP Tritrichomonas suis
2.4.2.8 Y156W site directed mutagenesis, slightly changed substrate affinities compared to wild-type Tritrichomonas suis

Inhibitors

EC Number Inhibitors Comment Organism Structure
2.4.2.8 ADP
-
 Tritrichomonas suis
2.4.2.8 AMP mutant K134S, competitive Tritrichomonas suis
2.4.2.8 Phenylglyoxal irreversible, complete inactivation, alkylation of Arg155, GMP protects, no alkylation of mutant R155K Tritrichomonas suis

KM Value [mM]

EC Number KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
2.4.2.8 additional information
-
 additional information wild-type and mutants: Km values for substrates hypoxanthine, guanine, xanthine, IMP, GMP, XMP Tritrichomonas suis
2.4.2.8 0.0346
-
 adenine mutant K134S Tritrichomonas suis
2.4.2.8 0.038
-
 hypoxanthine mutant K134S Tritrichomonas suis

Organism

EC Number Organism UniProt Comment Textmining
2.4.2.8 Tritrichomonas suis
-
-
-

Purification (Commentary)

EC Number Purification (Comment) Organism
2.4.2.8 recombinant wild-type enzyme and mutant/s from Escherichia coli Tritrichomonas suis

Reaction

EC Number Reaction Comment Organism Reaction ID
2.4.2.8 IMP + diphosphate = hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate catalytic mechanism Tritrichomonas suis
a
2.4.2.8 IMP + diphosphate = hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate active site structure Tritrichomonas suis
a

Specific Activity [micromol/min/mg]

EC Number Specific Activity Minimum [µmol/min/mg] Specific Activity Maximum [µmol/min/mg] Comment Organism
2.4.2.8 additional information
-
 kinetics Tritrichomonas suis

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2.4.2.8 adenine + 5-phospho-alpha-D-ribose 1-diphosphate
-
 Tritrichomonas suis ?
-
 ?
2.4.2.8 guanine + 5-phospho-alpha-D-ribose 1-diphosphate
-
 Tritrichomonas suis GMP + diphosphate
-
 r
2.4.2.8 hypoxanthine + 5-phospho-alpha-D-ribose 1-diphosphate
-
 Tritrichomonas suis IMP + diphosphate
-
 r
2.4.2.8 additional information kinetic study Tritrichomonas suis ?
-
 ?
2.4.2.8 xanthine + 5-phospho-alpha-D-ribose 1-diphosphate
-
 Tritrichomonas suis XMP + diphosphate
-
 r

Turnover Number [1/s]

EC Number Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
2.4.2.8 additional information
-
 additional information wild-type and mutants: kcat for substrates hypoxanthine, guanine, xanthine, IMP, GMP, XMP, diphosphate, 5-phosphoribosyl 1-diphosphate Tritrichomonas suis

Ki Value [mM]

EC Number Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
2.4.2.8 0.0254
-
 ADP mutant K134S, competitive versus 5-phospho-alpha-D-ribose 1-diphosphate Tritrichomonas suis