High molecular weight chlorins in a lacustrine shale
1991; Elsevier BV; Volume: 17; Issue: 6 Linguagem: Inglês
10.1016/0146-6380(91)90029-j
ISSN1873-5290
AutoresW.G. Prowse, James R. Maxwell,
Tópico(s)Marine and coastal ecosystems
ResumoThe major esterified tetrapyrrole in a Miocene oil shale (Maraú, Brazil) is a free base chlorin, most likely pyrophaeophorbide a, esterified to 24-ethyl-4α-methyl-5α(H)-cholestan-3β-ol, the structure being assigned by FAB-MS and 1H NMR, and by GC-MS analysis of the sterol liberated by hydrolysis. FAB-MS and electronic absorption spectrophotometric data for the second most abundant component are consistent with the mesopyrophaeophorbide counterpart. Only one other minor esterified chlorin was detected, implying a highly specific and, hence, biologically-mediated esterification. It is not clear whether the reaction took place during biosynthesis of an unknown precursor chlorophyll or resulted from esterification of a hydrolysis product(s) from a known chlorophyll (most likely chlorophyll a) after cellular disruption, although the second possibility is considered more likely.
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