Biogeochemistry of organic nitrogen compounds

Citation:
Bada, JL.  1998.  Biogeochemistry of organic nitrogen compounds. Nitrogen-Containing Macromolecules in the Bio- and Geosphere. 707( Stankiewicz BA, VanBergen PF, Eds.).:64-73., Washington: Amer Chemical Soc

Keywords:

amber, amino-acid racemization, ancient dna, deoxyribonucleic-acid, dna-sequences, entombed insects, kinetics, noncollagenous, preservation, protein, sugars

Abstract:

Nitrogen containing organic compounds represent the second most abundant reservoir of nitrogen on the surface of the Earth. However, the organic compounds that make up this global nitrogen pool are not well characterized. Although amino acids and the nitrogenous bases of nucleic acids make up only a few percent of the total organic nitrogen reservoir, the geochemical reactions of these compounds have been extensively studied. Because hydrolysis reactions are rapid on the geologic time scale, both proteins and nucleic acids (DNA and RNA) are not preserved for more than 10(3) to 10(5) years in most environments. The racemization reaction of amino acids converts the L-amino acids present in the biosphere into a racemic mixture (D/L amino acid ratio = 1.0) in the geosphere in less than 10(6) years. Anhydrous conditions, such as those that may be associated with amber entombed insects, may retard both biopolymer hydrolysis and racemization. Condensation reactions between amino acids and sugars, including sugars at apurinic sites in nucleic acid fragments, likely result in the incorporation of these compounds into geopolymers such as humic acids. Although rearrangement reactions in geopolymers may scramble the original molecular structures, part of the global organic nitrogen inventory was originally derived from amino acids and nucleic acid bases.

Notes:

n/a

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