The protein inhibitor of neuronal nitric oxide synthase (PIN): characterization of its action on pure nitric oxide synthases.
Neuronal NO synthase (nNOS) was discovered recently to interact specifically with the protein PIN (protein inhibitor of nNOS) [Jaffrey, S.R. and Snyder, S.H. (1996) Science 274, 774-777]. We have studied the effects on pure NOS enzymes of the same GST-tagged PIN used in the original paper. Unexpectedly, all NOS isoenzymes were inhibited. The IC50 for nNOS was 18 +/- 6 microM GST-PIN with 63 nM nNOS after 30 min at 37 degrees C. Uncoupled NADPH oxidation was inhibited similarly, whereas cytochrome c reductase activity, the K(M) for L-arginine, and dimerization were unaffected. We reconsider the physiological role of PIN in the light of these results.
Institut für Pharmakologie und Toxikologie, Karl-Franzens Universität Graz, Austria.
B
B
Hemmens
S
S
Woschitz
E
E
Pitters
B
B
Klösch
C
C
Völker
K
K
Schmidt
B
B
Mayer
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000378:metabolism; D019281:Dimerization; D029721:Drosophila Proteins; D004398:Dyneins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D009249:NADP / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D010084:Oxidation-Reduction; D051381:Rats; D011993:Recombinant Fusion Proteins
D002352:Carrier Proteins; D003574:Cytochrome c Group; D029721:Drosophila Proteins; D004791:Enzyme Inhibitors; D011993:Recombinant Fusion Proteins; D009249:NADP; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496322:Nos1 protein, rat; C496318:Nos2 protein, rat; C496316:Nos3 protein, rat; D004398:Dyneins