Different dissociation pathways and observation of an excited deoxy state in picosecond photolysis of oxy- and carboxymyoglobin.
Different dissociation pathways and observation of an excited deoxy state in picosecond photolysis of oxy- and carboxymyoglobin.
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氧肌红蛋白和碳氧肌红蛋白皮秒光解中不同的解离途径和激发脱氧状态的观察。
DOI：
10.1073/pnas.78.12.7526
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发表时间：
1981
影响因子：
11.1
通讯作者：
Hochstrasser,RM
中科院分区：
文献类型：
--
作者：
Cornelius,PA;Steele,AW;Chernoff,DA;Hochstrasser,RM
在353nm激发后，研究了Mb、MbCO和MbO2的皮秒瞬态吸收光谱，其延时可达10ns。特别值得注意的是，在MbCO和MbO2的前50ps期间，Soret区域发生的快速光谱变化。在MbCO中，Soret峰的漂白（特征I）和新的脱氧样吸收（特征II）的出现都是瞬间发生的，而在MbO2中，特征II相对于特征I是延迟的。在455nm附近，MbO2的短寿命（约12ps）特征（特征III）比MbCO强烈得多，并且在Mb的瞬态光谱中也被发现。在MbCO和MbO2中都没有发现亚纳秒双相重组的证据。这些观察结果与MbO2通过Mb激发态光解的方案一致，而MbCO在相同条件下直接产生基态Mb。结果和结论与以往皮秒研究这些分子和相关血红蛋白衍生物的结果进行了比较。
Picosecond transient absorption spectra of Mb, MbCO, and MbO2 have been studied at time delays of up to 10 ns after excitation at 353 nm. Particular attention has been paid to the rapid spectral changes that occur in the Soret region during the first 50 ps in MbCO and MbO2. In MbCO both the bleaching of the Soret peak (feature I) and the appearance of new deoxy-like absorption (feature II) occur instantaneously, whereas in MbO2 feature II is delayed with respect to feature I. A short-lived (approximately 12 ps) feature near 455 nm (feature III) was much more intense in MbO2 than in MbCO and was also identified in the transient spectrum of Mb. No evidence of subnanosecond geminate recombination was found in either MbCO or MbO2. These observations are consistent with a scheme in which MbO2 photodissociates through an excited state of Mb, whereas MbCO under the same conditions produces ground state Mb directly. The results and conclusions are compared with those of previous picosecond studies on these molecules and related hemoglobin derivatives.