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Nitric oxide synthase activity in mitochondria.

P Ghafourifar·C Richter
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Abstract

In the present study we show the existence of a functional nitric oxide synthase (NOS) in rat liver mitochondria. The enzyme uses L-arginine (L-arg) to produce nitric oxide (NO) and L-citrulline, and is Ca2+-dependent. L-Arg analogues, N(omega)monomethyl-L-arg and N(omega)-nitro-L-arg, inhibit the enzyme, and D-arginine is not a substrate for it. We found mitochondrial NOS (mtNOS) activity associated with the inner mitochondrial membrane but not with the matrix fraction. In intact, succinate-energized mitochondria, the enzyme is constitutively active and exerts substantial control over mitochondrial respiration and membrane potential. The activity is further stimulated when Ca2+ is taken up by mitochondria. We suggest that the existence of mtNOS and its Ca2+ dependence are highly relevant for mitochondrial functioning.

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AnimalsCalciumMitochondria, LiverNitric Oxide SynthaseRatsJournal ArticleResearch Support, Non-U.S. Gov't

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P Ghafourifar, C Richter. 1997-12-01. Nitric oxide synthase activity in mitochondria.. https://doi.org/10.1016/s0014-5793(97)01397-5

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