A REMARKABLE DEUTERIUM EFFECT ON THE RATE OF PHOTOSENSITIZED OXIDATION OF ALCOHOL DEHYDROGENASE AND TRYPSIN
A REMARKABLE DEUTERIUM EFFECT ON THE RATE OF PHOTOSENSITIZED OXIDATION OF ALCOHOL DEHYDROGENASE AND TRYPSIN
复制标题
氘对乙醇脱氢酶和胰蛋白酶光敏氧化速率的显着影响
DOI：
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发表时间：
1973
影响因子：
3.3
通讯作者：
D. Kearns
中科院分区：
文献类型：
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作者：
R. Nilsson;D. Kearns
有关蛋白质光敏氧化的文献很多（Spikes和利文斯顿，1969），尽管各种蛋白质分子中发生的变化已被很好地描述，但主要氧化实体的性质尚不清楚。可能涉及至少两种不同的反应途径，一种是蛋白质直接与敏化剂的三重态反应，另一种是涉及单线态激发氧的替代途径（Kearns，1969; Grossweiner，1969;克雷默，1972）。当然，也可以设想涉及混合机制的情况。在最近的研究中，我们测定了单线态氧的绝对寿命（默克尔和Kearns，1971，1972），并基于大溶剂氘对该激发态的寿命的影响，以及基于单线态氧的寿命与溶剂的红外吸收强度之间的相关性，开发了单线态氧的诊断测试（默克尔和Kearns，1972;默克尔等人，1972年）。将这些工具与叠氮化物淬灭单线态氧的现象一起使用（Hasty等人，1972）和动力学光谱法，获得了单线态氧参与游离氨基酸组氨酸、色氨酸和甲硫氨酸的光敏氧化的结论性证据（Nilsson等人，1972年）。在本研究报告中，我们使用了溶剂氘对单线态氧寿命的影响和叠氮化物淬灭来证明乙醇脱氢酶和胰蛋白酶的光动力失活涉及单线态氧。
THE literature dealing with the photosensitized oxidation of proteins is extensive (Spikes and Livingston, 1969) and, although the changes occurring in the various protein molecules have been well described, the nature of the primary oxidizing entity is not known. At least two different reaction paths may be involved-one in which the protein reacts directly with the triplet state of the sensitizer, and an alternative pathway involving singlet-state excited oxygen (Kearns, 1969; Grossweiner, 1969; Kramer, 1972). Naturally, cases involving a mixed mechanism may also be conceived. In recent investigations we have determined the absolute lifetime of singlet oxygen (Merkel and Kearns, 1971, 1972) and developed diagnostic tests for singlet oxygen based on the large solvent deuterium effect on the lifetime of this excited state, as well as on the correlation between the lifetime of singlet oxygen and the intensity of the infrared absorption of the solvent (Merkel and Kearns, 1972; Merkel et al., 1972). Using these tools together with the phenomenon of quenching of singlet oxygen by azide (Hasty et al., 1972) and kinetic spectroscopy, conclusive evidence for the participation of singlet oxygen in the photosensitized oxidation of the free amino acids histidine, tryptophan and methionine was obtained (Nilsson et al., 1972). In the present Research Note we have used the solvent deuterium effect on singlet oxygen lifetimes and azide quenching to demonstrate that the photodynamic inactivation of the enzymes alcohol dehydrogenase and trypsin involves singlet oxygen.