Production of nitric oxide (NO) during the oxidation of human oxyhemoglobin by nitrite: application of a NO-selective electrode for the measurement of NO.
By using a nitric oxide (NO) selective electrode system. NO produced during the oxidation of human hemoglobin by nitrite was monitored. When 160 microM oxyhemoglobin (in heme) was reacted with 500 microM nitrite. NO was generated quickly at the initial lag phase of the oxidation of oxyhemoglobin by nitrite and decreased gradually during the second burst phase of the reaction. While the oxidation of oxyhemoglobin by nitrite proceeded in a sigmoidal manner including the initial lag phase and second burst phase. The maximal amount of NO produced under this condition was estimated to be 48 microM. According to the increase of nitrite concentrations added, the amounts of NO produced at the initial phase increased, being in good accordance with the increased rate of the oxidation of oxyhemoglobin. These results strongly suggest the critical role of NO in the oxidation mechanism of oxyhemoglobin by nitrite.
Tomoda
A
A
Department of Biochemistry, Tokyo Medical College, Japan.
Murakami
E
E
Shibuya
T
T
D004566:Electrodes; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000378:metabolism*; D010783:Photometry; D013481:Superoxides / Q000378:metabolism; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism
D009573:Nitrites; D010108:Oxyhemoglobins; D013481:Superoxides; D019820:Xanthine; D009569:Nitric Oxide; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase