title: In vitro formation of S-nitrosohemoglobin in red cells by inducible nitric oxide synthase.
abstract: The present study demonstrates that NO produced in vitro by inducible nitric oxide synthase in red cells can convert hemoglobin contained in the red cells to S-nitrosohemoglobin. Experiments carried out either in the absence or in the presence of a low molecular weight thiol, such as cysteine, showed that in the first case the target of NO is heme-Fe2+. On the contrary, in the presence of cysteine, the first step is the formation of S-nitrosocysteine, followed by transfer of the NO group to a particular cysteine residue of beta-globin, cysteine 93. These results confirm previous data indicating the preferential formation of S-nitrosohemoglobin at that site by chemical methods [Ferranti et al. (1997) FEBS Lett. 400, 17-24], and the existence of a physiological mechanism of inactivation for NO circulating in blood. The analysis of S-nitrosohemoglobin can also allow the quantification of the NO levels in blood to be applied for in vitro and in vivo measurements.
authors.affiliation: Centro Internationale di Servizi di Spettrometria di Massa, CNR, Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Mamone
authors.forename: N
authors.initials: N
authors.lastname: Sannolo
authors.forename: A
authors.initials: A
authors.lastname: Malorni
authors.forename: P
authors.initials: P
authors.lastname: Ferranti
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000201:enzymology / Q000378:metabolism*; D006454:Hemoglobins / Q000096:biosynthesis* / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D008623:Mercaptoethanol; D019001:Nitric Oxide Synthase / Q000737:chemistry / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II; D009603:Nitroso Compounds / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D026403:S-Nitrosothiols
chemical_list: D006454:Hemoglobins; D009603:Nitroso Compounds; D026403:S-Nitrosothiols; C103574:S-nitrosohemoglobin; D008623:Mercaptoethanol; C032635:S-nitrosomercaptoethanol; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II