Methodologies for the sensitive and specific measurement of S-nitrosothiols, iron-nitrosyls, and nitrite in biological samples

BK Yang, EX Vivas, CD Reiter, MT Gladwin - Free radical research, 2003 - Taylor & Francis
BK Yang, EX Vivas, CD Reiter, MT Gladwin
Free radical research, 2003Taylor & Francis
Nitric oxide (NO) is a soluble gas that is synthesized by the nitric oxide synthase enzyme
systems in endothelial, neuronal, and immune cells and is a critical endogenous
vasodilator.[1–3] While it is generally believed that endothelium-derived NO is the primary
regulator of NO-mediated basal blood flow,[4, 5] recent studies have focused on the role of
intravascular NO-derived molecules that could stabilize NO bioactivity and contribute to
blood flow and oxygen delivery. These species include plasma S-nitrosothiols,[6–10] nitrite …
Nitric oxide (NO) is a soluble gas that is synthesized by the nitric oxide synthase enzyme systems in endothelial, neuronal, and immune cells and is a critical endogenous vasodilator.[1–3] While it is generally believed that endothelium-derived NO is the primary regulator of NO-mediated basal blood flow,[4, 5] recent studies have focused on the role of intravascular NO-derived molecules that could stabilize NO bioactivity and contribute to blood flow and oxygen delivery. These species include plasma S-nitrosothiols,[6–10] nitrite [4, 11] and NO hemoglobin adducts. NO reacts reversibly with hemoglobin to form an NO-heme adduct, ironnitrosyl-hemoglobin (HbFeIINO), and can nitrosate a surface thiol on cysteine-93 of the b-globin chain to form S-nitrosohemoglobin (SNO-Hb). A model has been proposed that NO can be delivered by SNO-Hb in an oxygen-dependent manner, providing the red cell with oxygen sensor and NO donor properties.[12–14] This model rises from the observation that gradients of SNO-Hb exist from artery to vein with levels in oxygenated blood ranging from 300nM to 2.5 mM and levels in venous blood that are not measurable.[12]
However, the evidence for a dynamic vascular cycle of SNO-Hb is brought into question by widely varying reports for the basal levels of intracellular SNO-Hb in arterial and venous blood.[12, 15, 8, 9] We have employed highly sensitive methodologies that reduce the S–NO bond from hemoglobin in solutions of I2
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