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A model for the origin of photosynthesis--III. The ultraviolet photochemistry of uroporphyrinogenThe photochemical ramifications of the high ultraviolet flux on the primordial earth prior to the formation of the ozone layer have been considered in a study of the ultraviolet photochemistry of uroporphyrinogen (urohexahydroporphyrin), a colorless compound which absorbs strongly at wavelengths less than 220 nanometers. Urohexahydroporphyrin was investigated since it is the first macrocycle formed on the biosynthetic pathway of chlorophyll and can be used to test the hypothesis that the biosynthetic pathway to chlorophyll recapitulates the evolutionary history of photosynthesis. When urohexahydroporphyrin is illuminated in aqueous anaerobic solution, hydrogen gas is produced. More hydrogen gas is produced in the presence of a colloidal platinum catalyst. The products of the photooxidation of urohexahydroporphyrin are urotetrahydroporphyrin (uroporphomethene) and uroporphyrin. This research shows how the oxidation of uroporphyrinogen to uroporphyrin, the first biogenetic porphyrin, could have occurred anaerobically and abiotically on the primordial earth.
Document ID
20040121546
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
Authors
Mercer-Smith, J. A.
(Los Alamos National Laboratory NM 87545, United States)
Raudino, A.
Mauzerall, D. C.
Date Acquired
August 22, 2013
Publication Date
January 1, 1985
Publication Information
Publication: Photochemistry and photobiology
Volume: 42
Issue: 3
ISSN: 0031-8655
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NAGW-321
Distribution Limits
Public
Copyright
Other

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