McCarthy S A, Belanger F C, Rebeiz C A
Biochemistry. 1981 Aug 18;20(17):5080-7. doi: 10.1021/bi00520a039.
The discovery of a novel metalloporphyrin pool in etiolated cucumber cotyledons and in dark-grown Euglena gracilis is described. The novel pool exhibited the chromatographic properties of a fully esterified metalloporphyrin, devoid of free carboxylic groups, and the spectrophotometric and spectrofluorometric properties of a magnesium protoporphyrin. Demetalation and hydrolysis indicated that the tetrapyrrole moiety of the metalloporphyrin was a protoporphyrin diester. High-pressure liquid chromatography of the fully esterified metalloporphyrin pool and gas chromatographic/mass spectroscopic analysis of the saponified alcohol fraction revealed that the latter was made up of three major long-chain alcohols. None of those alcohols was identifiable, however, with known isoprenoids such as geraniol, farnesol, or phytol. Similar analysis of the saponified alcohol fraction of the protochlorophyllide ester pool likewise revealed the presence of three major long-chain alcohols none of which was identifiable with known isoprenoid alcohols or with the alcohols of the novel metalloporphyrin pool. On the basis of the above observations, the novel metalloporphyrin pool was tentatively identified as a magnesium protoporphyrin diester pool. It is suggested that this pool is a metabolic intermediate of the fully esterified branch of the chlorophyll biosynthetic pathway [Rebeiz, C. A., Smith, B. B., Matthesis, I. R., Cohen, C. E., & McCarthy, S. A. (1978) in Chloroplast Development (Akoyunoglou, G., & Argyroudi-Akoyunoglou, J. H., Eds.) pp 56-76, Elsevier/North-Holland Bio-Medical Press, Amsterdam] and is probably the precursor of the protochlorophyllide ester pool in plants.
本文描述了在黄化黄瓜子叶和黑暗培养的纤细裸藻中发现的一种新型金属卟啉库。该新型库具有完全酯化的金属卟啉的色谱特性，不含游离羧基，以及镁原卟啉的分光光度和荧光光谱特性。脱金属和水解表明，金属卟啉的四吡咯部分是原卟啉二酯。对完全酯化的金属卟啉库进行高压液相色谱分析，以及对皂化醇馏分进行气相色谱/质谱分析，结果表明后者由三种主要的长链醇组成。然而，这些醇均无法与香叶醇、法呢醇或叶绿醇等已知类异戊二烯相鉴别。对原叶绿素酸酯库的皂化醇馏分进行类似分析，同样发现存在三种主要的长链醇，其中没有一种能与已知的类异戊二烯醇或新型金属卟啉库中的醇相鉴别。基于上述观察结果，该新型金属卟啉库被初步鉴定为镁原卟啉二酯库。有人认为，这个库是叶绿素生物合成途径完全酯化分支的代谢中间体[Rebeiz, C. A., Smith, B. B., Matthesis, I. R., Cohen, C. E., & McCarthy, S. A. (1978) in Chloroplast Development (Akoyunoglou, G., & Argyroudi-Akoyunoglou, J. H., Eds.) pp 56 - 76, Elsevier/North-Holland Bio-Medical Press, Amsterdam]，可能是植物中原叶绿素酸酯库的前体。
