Pyruvate kinase activity is an important element in the flux control of the intermediate metabolism. The purified enzyme from Corynebacterium glutamicum demonstrated a marked sigmoidal dependence of the initial rate on the phosphoenolpyruvate concentration. In the presence of the negative allosteric effector ATP, the phosphoenolpyruvate concentration at the half-maximum rate (S0.5) increased from 1.2 to 2.8 mM, and cooperation, as expressed by the Hill coefficient, increased from 2.0 to 3.2. AMP promoted opposite effects: the S0.5 was decreased to 0.4 mM, and the enzyme exhibited almost no cooperation. The maximum reaction rate was 702 U/mg, which corresponded to an apparent kcat of 2,540 s-1. The enzyme was not influenced by fructose-1,6-diphosphate and used Mn2+ or Co2+ as cations. Sequence determination of the C. glutamicum pyk gene revealed an open reading frame coding for a polypeptide of 475 amino acids. From this information and the molecular mass of the native protein, it follows that the pyruvate kinase is a tetramer of 236 kDa. Comparison of the deduced polypeptide sequence with the sequences of other bacterial pyruvate kinases showed 39 to 44% homology, with some regions being very strongly conserved.
| Predicate | Object |
|---|---|
| rdf:type | |
| rdfs:comment |
Pyruvate kinase activity is an important element in the flux control of the intermediate metabolism. The purified enzyme from Corynebacterium glutamicum demonstrated a marked sigmoidal dependence of the initial rate on the phosphoenolpyruvate concentration. In the presence of the negative allosteric effector ATP, the phosphoenolpyruvate concentration at the half-maximum rate (S0.5) increased from 1.2 to 2.8 mM, and cooperation, as expressed by the Hill coefficient, increased from 2.0 to 3.2. AMP promoted opposite effects: the S0.5 was decreased to 0.4 mM, and the enzyme exhibited almost no cooperation. The maximum reaction rate was 702 U/mg, which corresponded to an apparent kcat of 2,540 s-1. The enzyme was not influenced by fructose-1,6-diphosphate and used Mn2+ or Co2+ as cations. Sequence determination of the C. glutamicum pyk gene revealed an open reading frame coding for a polypeptide of 475 amino acids. From this information and the molecular mass of the native protein, it follows that the pyruvate kinase is a tetramer of 236 kDa. Comparison of the deduced polypeptide sequence with the sequences of other bacterial pyruvate kinases showed 39 to 44% homology, with some regions being very strongly conserved.
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| skos:exactMatch | |
| uniprot:name |
Appl. Environ. Microbiol.
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| uniprot:author |
Gubler M.E.,
Jetten M.S.,
Lee S.H.,
Sinskey A.J.
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| uniprot:date |
1994
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| uniprot:pages |
2501-2507
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| uniprot:title |
Structural and functional analysis of pyruvate kinase from Corynebacterium glutamicum.
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| uniprot:volume |
60
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