| Autor: |
Jebeleanu, G., Ty, N. G., Mantsch, H. H., Bârzu, O., Niac, G., Abrudan, I. |
| Zdroj: |
Proceedings of the National Academy of Sciences of the United States of America; November 1974, Vol. 71 Issue: 11 p4630-4634, 5p |
| Abstrakt: |
The modified adenine nucleotides ATP-NO, ADP-NO, and AMP-NO were tested as potential substrates and/or inhibitors of mitochondrial phosphotransferases. ADP-NO is not recognized by the translocase system located in the inner mitochondrial membrane; however, it is rapidly phosphorylated to ATP-NO in the outer compartment of mitochondria, by way of the nucleosidediphosphate kinase (EC 2.7.4.6) reaction, provided there is sufficient ATP in the mitochondria. AMP-NO is not phosphorylated by liver mitochondria to the corresponding nucleoside diphosphate; it cannot serve as substrate for adenylate kinase (EC 2.7.4.3). ATP-NO and ADP-NO, however, are substrates of this enzyme. The apparent equilibrium constant for the reaction, ADP-NO + ADP ⇌ ATP-NO + AMP, of 0.908 at pH 7.4 and 5 mM Mg2+is significantly higher than that of the reaction with natural nucleotides.Although adenosine N1-oxide is easily phosphorylated to AMP-NO by adenosine kinase [Schnebli et al.(1967) J. Biol. Chem.242, 1997-2004], the formation of corresponding nucleoside triphosphate in vivoseems also to be limited by adenylate kinase; adenosine N1-oxide cannot replace adenosine in restoring the normal ATP level in ethionine-treated rats. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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