Oxidation of NG-hydroxy-L-arginine by nitric oxide synthase: evidence for the involvement of the heme in catalysis.
Oxidation of NG-hydroxy-L-arginine by nitric oxide synthase: evidence for the involvement of the heme in catalysis.
复制标题
一氧化氮合酶氧化 NG-羟基-L-精氨酸：血红素参与催化的证据。
DOI：
10.1006/bbrc.1993.1719
复制
发表时间：
1993
影响因子：
3.1
通讯作者：
Marletta,MA
中科院分区：
文献类型：
--
作者：
Pufahl,RA;Marletta,MA
通过一氧化碳（CO）抑制研究和结合差光谱研究了巨噬细胞一氧化氮合酶（NOS）的原卟啉IX血红素铁参与NG-羟基-L-精氨酸（L-NHA）氧化为一氧化氮（NO）和瓜氨酸。发现CO：氧气混合物（80：20）对作为底物的L-NHA的反应抑制33%，而对L-精氨酸的反应抑制57%。光谱扰动后观察到的L-NHA氧化NOS，产生的I型结合差异光谱的最大值在384 nm和最小值在420 nm。此外，在不存在NADPH的情况下，L-NHA无法还原厌氧氧化型NOS。这些研究支持血红素参与L-NHA氧化为NO和瓜氨酸，表明血红素在NOS反应的两个目前表征的氧化步骤中起作用。
The involvement of the protoporphyrin IX heme iron of macrophage nitric oxide synthase (NOS) in the oxidation of NG-hydroxy-L-arginine (L-NHA) to nitric oxide (NO) and citrulline was investigated by carbon monoxide (CO) inhibition studies and binding difference spectroscopy. A CO:oxygen mixture (80:20) was found to inhibit the reaction by 33% with L-NHA as a substrate compared to 57% with L-arginine. Spectral perturbations were observed upon the addition of L-NHA to oxidized NOS, producing a type I binding difference spectrum with a maximum at 384 nm and minimum at 420 nm. In addition, L-NHA was incapable of reducing anaerobic oxidized NOS in the absence of NADPH. These studies support the involvement of the heme in the oxidation of L-NHA to NO and citrulline, indicating that the heme functions in both of the currently characterized oxidative steps of the NOS reaction.