Kreutzer Ulrike, Jue Thomas
Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA 95616-8635, USA.
Pflugers Arch. 2006 Apr;452(1):36-42. doi: 10.1007/s00424-005-0011-z. Epub 2006 Feb 9.
Because nitric oxide (NO) can react with myoglobin (Mb) to oxidize the heme Fe(II) to Fe(III), the appearance of metmyoglobin (metMb) during bradykinin stimulation underpins the hypothesis that Mb acts as an NO scavenger in the cell. Although some experiments have detected the reporter metMb signal in the -3.7 ppm spectral region, others have not corroborated the finding. Because metMb also has characteristic hyperfine-shifted signals in the 40-100 ppm spectral region, detection of these signals would confirm the presence of metMb. Perfused rat myocardium study has examined this spectral region in a range of bradykinin infusion protocols. Although bradykinin elicits a set of physiological responses, consistent with the induction of NO, the (1)H nuclear magnetic resonance spectra in all experiments reveal no detectable metMb signals. Moreover, in the perfused myocardium model, the bradykinin-induced decline in myocardial oxygen consumption does not appear to arise only from NO binding to cytochrome oxidase.
由于一氧化氮（NO）可与肌红蛋白（Mb）反应，将血红素铁（II）氧化为铁（III），因此缓激肽刺激过程中高铁肌红蛋白（metMb）的出现支持了Mb在细胞中作为NO清除剂的假说。尽管一些实验在-3.7 ppm光谱区域检测到了报告的高铁肌红蛋白信号，但其他实验并未证实这一发现。由于高铁肌红蛋白在40 - 100 ppm光谱区域也有特征性的超精细位移信号，检测到这些信号将证实高铁肌红蛋白的存在。灌注大鼠心肌研究在一系列缓激肽输注方案中检查了该光谱区域。尽管缓激肽引发了一系列与NO诱导一致的生理反应，但所有实验中的氢核磁共振光谱均未显示可检测到的高铁肌红蛋白信号。此外，在灌注心肌模型中，缓激肽诱导的心肌耗氧量下降似乎并非仅由NO与细胞色素氧化酶结合引起。
