Cloned (Comment) | Organism |
---|---|
gene Rv1436, recombinant expression of N-terminally His6-tagged wild-type and mutant enzymes in Escherichia coli | Mycobacterium tuberculosis |
Protein Variants | Comment | Organism |
---|---|---|
C158A | site-directed mutagenesis, inactive mutant | Mycobacterium tuberculosis |
C162A | site-directed mutagenesis, the mutant exhibits a comparable Vmax to the wild-type enzyme and only a 2fold increased Km value for D-glyceraldehyde 3-phosphate | Mycobacterium tuberculosis |
H185A | site-directed mutagenesis, inactive mutant | Mycobacterium tuberculosis |
Inhibitors | Comment | Organism | Structure |
---|---|---|---|
arsenate | linear substrate inhibition, competitive versus phosphate | Mycobacterium tuberculosis | |
iodoacetamide | an irreversible, cysteine-specific alkylator, inactivation kinetics for inactivation of mutant C162A | Mycobacterium tuberculosis | |
NADH | noncompetitive inhibition versus D-glyceraldehyde 3-phosphate, competitive inhibition versus both NAD+ and arsenate | Mycobacterium tuberculosis | |
phosphate | linear substrate inhibition, competitive versus arsenate | Mycobacterium tuberculosis |
KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | kinetic isotope effects. The enzyme exhibits a kinetic mechanism in which first NAD+, then D-glyceraldehyde 3-phosphate bind to the active site resulting in the formation of a covalently bound thiohemiacetal intermediate. After oxidation of the thiohemiacetal and subsequent nucleotide exchange (NADH off, NAD+ on), the binding of inorganic phosphate and phosphorolysis yields the product 3-phospho-D-glyceroyl phosphate. Solvent and multiple kinetic isotope effects revealed that the first halfreaction is rate limiting and utilizes a step-wise mechanism for thiohemiacetal oxidation via a transient alkoxide to promote hydride transfer and thioester formation. steady-state kinetics | Mycobacterium tuberculosis | |
6 | - |
phosphate | pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
D-glyceraldehyde 3-phosphate + phosphate + NAD+ | Mycobacterium tuberculosis | - |
3-phospho-D-glyceroyl phosphate + NADH + H+ | - |
r | |
D-glyceraldehyde 3-phosphate + phosphate + NAD+ | Mycobacterium tuberculosis H37Rv | - |
3-phospho-D-glyceroyl phosphate + NADH + H+ | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Mycobacterium tuberculosis | P9WN83 | - |
- |
Mycobacterium tuberculosis H37Rv | P9WN83 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant N-terminally His6-tagged wild-type and mutant enzymes from Escherichia coli by nickel affinity chromatography and dialysis to over 965% purity | Mycobacterium tuberculosis |
Reaction | Comment | Organism | Reaction ID |
---|---|---|---|
D-glyceraldehyde 3-phosphate + phosphate + NAD+ = 3-phospho-D-glyceroyl phosphate + NADH + H+ | the conserved residue C158 is responsible for nucleophilic catalysis and the conserved residue H185 acts as a catalytic base. The enzyme exhibits a kinetic mechanism in which first NAD+, then D-glyceraldehyde 3-phosphate bind to the active site resulting in the formation of a covalently bound thiohemiacetal intermediate. After oxidation of the thiohemiacetal and subsequent nucleotide exchange (NADH off, NAD+ on), the binding of inorganic phosphate and phosphorolysis yields the product 3-phospho-D-glyceroyl phosphate. Solvent and multiple kinetic isotope effects revealed that the first halfreaction is rate limiting and utilizes a step-wise mechanism for thiohemiacetal oxidation via a transient alkoxide to promote hydride transfer and thioester formation | Mycobacterium tuberculosis |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
D-glyceraldehyde 3-phosphate + arsenate + NAD+ | - |
Mycobacterium tuberculosis | 1-arseno-3-phosphoglycerate + NADH + H+ | - |
r | |
D-glyceraldehyde 3-phosphate + arsenate + NAD+ | - |
Mycobacterium tuberculosis H37Rv | 1-arseno-3-phosphoglycerate + NADH + H+ | - |
r | |
D-glyceraldehyde 3-phosphate + phosphate + NAD+ | - |
Mycobacterium tuberculosis | 3-phospho-D-glyceroyl phosphate + NADH + H+ | - |
r | |
D-glyceraldehyde 3-phosphate + phosphate + NAD+ | - |
Mycobacterium tuberculosis H37Rv | 3-phospho-D-glyceroyl phosphate + NADH + H+ | - |
r |
Synonyms | Comment | Organism |
---|---|---|
GAPDH | - |
Mycobacterium tuberculosis |
glyceraldehyde 3-phosphate dehydrogenase | - |
Mycobacterium tuberculosis |
Mtb-GAPDH | - |
Mycobacterium tuberculosis |
Rv1436 | - |
Mycobacterium tuberculosis |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
8 | - |
assay at | Mycobacterium tuberculosis |
pH Minimum | pH Maximum | Comment | Organism |
---|---|---|---|
5.5 | 8.5 | lack of any pH dependence of the kinetic parameters in the pH range tested, recombinant His6-tagged wild-type enzyme | Mycobacterium tuberculosis |
pH Stability | pH Stability Maximum | Comment | Organism |
---|---|---|---|
5.5 | 8.5 | pH stability range of purified recombinant His6-tagged wild-type enzyme | Mycobacterium tuberculosis |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
additional information | no activity with NADP+ | Mycobacterium tuberculosis | |
NAD+ | - |
Mycobacterium tuberculosis | |
NADH | - |
Mycobacterium tuberculosis |
Ki Value [mM] | Ki Value maximum [mM] | Inhibitor | Comment | Organism | Structure |
---|---|---|---|---|---|
0.014 | - |
NADH | versus NAD+, pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis | |
0.024 | - |
NADH | versus D-glyceraldehyde 3-phosphate, pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis | |
0.037 | - |
NADH | versus arsenate, pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis | |
60 | - |
phosphate | pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis | |
93 | - |
arsenate | pH 8.0, temperature not specified in the publication, recombinant His-tagged wild-type enzyme | Mycobacterium tuberculosis |
General Information | Comment | Organism |
---|---|---|
metabolism | the enzyme is involved in glycolysis | Mycobacterium tuberculosis |
additional information | kinetic and chemical mechanism of Mtb-GAPDH, overview. C158 is the active site nucleophile reacting with the aldehyde group of D-glyceraldehyde 3-phosphate to generate the thiohemiacetal and H185 is additionally required to either stabilize thiolate anion formation or act as a catalytic acid/base group | Mycobacterium tuberculosis |