Electron spin resonance study of the role of NO. catalase in the activation of guanylate cyclase by NaN/sub 3/ and NH/sub 2/OH
The role of NO.catalase in the activation of partially purified soluble guanylate cyclase of rat liver by NaN/sub 3/ and NH/sub 2/OH was examined by electron spin resonance (ESR) spectroscopy. The stimulation of partially purified guanylate cyclase by NO.catalase was similar to that obtained with NO.hemeoglobin and with NO.cytochrome P-420. By contrast, these same enzyme preparations did not respond to NO or catalase alone. Addition of hematin or hemoglobin plus a reducing agent to purified guanylate cyclase restored enzyme responsiveness to NO and N-methyl-N'-nitro-N-nitro-soguanidine (MNNG), but not to NaN/sub 3/ or NH/sub 2/OH. Formation of the NO.catalase complex was evident by ESR spectroscopy in test solutions containing NaN/sub 3/ or NH/sub 2/OH, catalase, and a glucose-glucose oxidase, H/sub 2/O/sub 2/-generating system. These results provide evidence for catalase-dependent NO generation from NaN/sub 3/ and NH/sub 2/OH under conditions leading to guanylate cyclase activation. Preformed NO.hemoglobin or NO.cytochrome P-420 also activated heme-deficient partially purified guanylate cyclase. In the absence of the NO ligand, both hemoglobin and catalase suppress the stimulatory effects of the corresponding NO.heme proteins on guanylate cyclase. However, hemoglobin is approximately 2000 times more effective as an inhibitor of NO.hemoglobin stimulation of guanylate cyclase than is catalase as an inhibitor of NO.catalase action.The results imply that guanylate cyclase responses to activators that can form NO are determined by both the stimulatory activity of the endogenous heme acceptors of NO and the relative inhibitory effects of the unliganded heme proteins present. (DS)
- Research Organization:
- Univ. of Pittsburgh, PA
- OSTI ID:
- 5308355
- Journal Information:
- J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 254:17; ISSN JBCHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of hydroxyl radical scavengers KCN and CO on ultraviolet light-induced activation of crude soluble guanylate cyclase
The crystal structure of the catalytic domain of a eukaryotic guanylate cyclase
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
CARBOXYLIC ACIDS
CATALASE
CATALYSIS
CHALCOGENIDES
COMPLEXES
ELECTRON SPIN RESONANCE
ENZYME INHIBITORS
ENZYMES
GLOBIN
HEME
HEMOGLOBIN
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
INHIBITION
KINETICS
MAGNETIC RESONANCE
MAMMALS
METABOLISM
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PIGMENTS
PORPHYRINS
PROTEINS
RATS
REACTION KINETICS
RESONANCE
RESPONSE MODIFYING FACTORS
RODENTS
VERTEBRATES