Margalit R, Cohen S
J Inorg Biochem. 1985 Nov;25(3):187-95. doi: 10.1016/0162-0134(85)80012-x.
The appearance of new additional bands, at 580 and 630 nm, in the fluorescence spectra of porphyrins, upon the aging of their aqueous solutions, was investigated for four porphyrin systems: The deutero, the hemato, the hemato-derivative, and the proto. The conditions for quantitative conversion to the new spectra were sought. To that end the concentration levels investigated were adjusted to have each porphyrin system in a monomer-dominant state. The species fluorescing at 580 nm was denoted f580 and its rate of appearance was found to fit first-order kinetics, for each porphyrin, the range of the rate constants being 0.03-0.10 hr-1. Two key issues were probed: (a) The identity of f580, the effort directed towards zincporphyrin. (b) Its origins--a contaminant unmasked, or a species newly formed, during the aging. Testing f580 for zincporphyrin properties, spectral at neutral pH, acid/base de/remetalation, EDTA competition, and chromatography gave in each case positive results, allowing the identification of f580 as zincporphyrin. On the basis of the data obtained and the known sources for the contamination of aqueous solutions by zinc, the case is made for zinc porphyrin formation upon aging. The relevance of the phenomena to the therapeutic activities of porphyrins is discussed.
针对四种卟啉体系（氘代卟啉、血卟啉、血卟啉衍生物和原卟啉），研究了其水溶液老化时在580纳米和630纳米处卟啉荧光光谱中出现新的附加谱带的情况。探寻了定量转化为新光谱的条件。为此，将所研究的浓度水平调整为使每个卟啉体系处于单体主导状态。在580纳米处发荧光的物质记为f580，发现其出现速率符合一级动力学，对于每种卟啉，速率常数范围为0.03 - 0.10小时⁻¹。探讨了两个关键问题：（a）f580的身份，研究方向指向锌卟啉。（b）其来源——老化过程中被揭示的污染物，还是新形成的物质。对f580进行锌卟啉性质测试，包括中性pH下的光谱、酸碱去金属化/再金属化、EDTA竞争和色谱分析，每种情况下均得到阳性结果，从而将f580鉴定为锌卟啉。根据所获得的数据以及水溶液中锌污染的已知来源，提出了老化时形成锌卟啉的情况。讨论了这些现象与卟啉治疗活性的相关性。
