Nitric oxide synthase activity in mitochondria

FEBS Letters

Ghafourifar, Pedram¹  Richter, Christoph¹ 

[1] Laboratory of Biochemistry I, Swiss Federal Institute of Technology (ETH), 8092 Zurich, Switzerland

关键词: Nitric oxide;    Mitochondrial respiration;    Mitochondrial membrane potential;    BM;    broken mitochondria;    ΔΨ;    mitochondrial membrane potential;    IM;    intact mitochondria;    l-NMMA;    N ω-monomethyl-l-arginine;    metHb;    methemoglobin;    mtNOS;    mitochondrial nitric oxide synthase;    MP;    mitoplast;    NO;    nitric oxide (synonym nitrogen monoxide);    l-NA;    N ω-nitro-l-arginine;    NOS;    nitric oxide synthase;    HbO2;    oxyhemoglobin;    SMP;    submitochondrial particles;    SOD;    superoxide dismutase;   

DOI  :  10.1016/S0014-5793(97)01397-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

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 ^ω-monomethyl-l-arg and N ^ω-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.

【 授权许可】

Unknown