CHEMICAL MECHANISMS FOR CYTOCHROME-P-450 OXIDATION - SPECTRAL AND CATALYTIC PROPERTIES OF A MANGANESE-SUBSTITUTED PROTEIN
CHEMICAL MECHANISMS FOR CYTOCHROME-P-450 OXIDATION - SPECTRAL AND CATALYTIC PROPERTIES OF A MANGANESE-SUBSTITUTED PROTEIN
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DOI：
10.1073/pnas.79.19.5758
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发表时间：
1982-01-01
期刊：
影响因子：
--
通讯作者：
SLIGAR, SG
中科院分区：
文献类型：
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作者：
GELB, MH;TOSCANO, WA;SLIGAR, SG
细菌[恶臭假单胞菌]细胞色素P-450诱导樟脑（P-450 CAM）与锰原卟啉IX重建，产生的酶，显示独特的光谱特性相对于先前表征的锰卟啉系统。一氧化氮复合物的Mn（II）-蛋白质显示超金属卟啉光谱暗示巯基连接的卟啉结合的锰离子。在碘代苯作为活性氧源的存在下，Mn取代的细胞色素P-450 cam作为酶结合的烯烃底物的环氧化的催化剂。这种反应性通过类似于Mn（V）-氧代络合物的光谱可检测的中间体进行;这些络合物已经用在有机溶液中采用人工Mn金属卟啉的模型系统得到了很好的证明。有趣的是，锰取代的细胞色素-P-450凸轮显示没有羟基化活性，无论是在重建樟脑羟化酶系统与吡啶核苷酸或在碘酰苯和Mn（III）形式的蛋白质的存在下。
Bacterial [Pseudomonas putida] cytochrome P-450 induced by camphor (P-450cam) is reconstituted with Mn protoporphyrin IX, yielding an enzyme that displays unique spectral properties relative to previously characterized Mn porphyrin systems. The nitric oxide complex of the Mn (II)-protein shows a hyper-metalloporphyrin spectrum suggestive of thiolate ligation to the porphyrin-bound Mn ion. In the presence of iodosobenzene as a source of active oxygen, Mn-substituted cytochrome P-450cam serves as a catalyst for the epoxidation of an enzyme-bound olefin substrate. This reactivity proceeds through a spectrally detectable intermediate that resembles the Mn (V)-oxo complexes; these complexes have been well documented with model systems employing artificial Mn metalloporphyrins in organic solution. Interestingly, Mn-substituted cytochrome-P-450cam shows no hydroxylation activity either in the reconstituted camphor hydroxylase system with pyridine nucleotide or in the presence of iodosobenzene and the Mn(III) form of the protein.