Scavenging of nitric oxide by hemoglobin in the tunica media of porcine coronary arteries.
Nitric Oxide
; 54: 8-14, 2016 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-26805578
ABSTRACT
Scavenging of nitric oxide (NO) often interferes with studies on NO signaling in cell-free preparations. We observed that formation of cGMP by NO-stimulated purified soluble guanylate cyclase (sGC) was virtually abolished in the presence of cytosolic preparations of porcine coronary arteries, with the scavenging activity localized in the tunica media (smooth muscle layer). Electrochemical measurement of NO release from a donor compound and light absorbance spectroscopy showed that cytosolic preparations contained a reduced heme protein that scavenged NO. This protein, which reacted with anti-human hemoglobin antibodies, was efficiently removed from the preparations by haptoglobin affinity chromatography. The cleared cytosols showed only minor scavenging of NO according to electrochemical measurements and did not decrease cGMP formation by NO-stimulated sGC. In contrast, the column flow-through caused a nearly 2-fold increase of maximal sGC activity (from 33.1 ± 1.6 to 54.9 ± 2.2 µmol × min(-1) × mg(-1)). The proteins retained on the affinity column were identified as hemoglobin α and ß subunits. The results indicate that hemoglobin, presumably derived from vasa vasorum erythrocytes, is present and scavenges NO in preparations of porcine coronary artery smooth muscle. Selective removal of hemoglobin-mediated scavenging unmasked stimulation of maximal NO-stimulated sGC activity by a soluble factor expressed in vascular tissue.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Hemoglobinas
/
Túnica Média
/
Vasos Coronários
/
Óxido Nítrico
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Nitric Oxide
Assunto da revista:
BIOQUIMICA
/
QUIMICA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Áustria