Isolation and structure determination of the unstable 13, 17-Cyclopheophorbide a enol from recent sediments
نویسندگان
چکیده
We observed that the unstable 13, 17-cyclopheophorbide a enol is one of the most abundant pigments in recent sediments (Black Sea, Mediterranean Sea, Peru margin) and here we report its isolation and structure determination (high-performance liquid chromatography, ultraviolet-visible spectrometry, mass spectrometry, and nuclear magnetic resonance). This enol has been considered as the precusor of sedimentary chlorins and porphyrins bearing either a seven 1 fiveor a seven-membered ring system. Analysis of sediment trap samples collected from the Peru Upwelling area revealed relatively high concentrations of 13, 17cyclopheophorbide a enol in trap samples containing high concentrations of metabolically derived carotenoid transformation products. The abundance of 13, 17-cyclopheophorbide a enol in sediment trap samples and recent sediments suggests that formation of an exocyclic seven-membered ring is a major diagenetic pathway for chlorophylls. Biologically mediated transformations of chlorophylls can therefore yield products not included in the classical Triebs degradation scheme for cyclic tetrapyrroles. Copyright © 1999 Elsevier Science Ltd
منابع مشابه
On the sedimentary occurrence of chlorophyllone a.
The 13(2),17(3)-cyclopheophorbide a enol (CPP) is shown to convert mainly to a approximately 1:1 mixture of (13(2)R/S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15(1)-hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that th...
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