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BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA http://dx.doi.org/10.18268/BSGM2009v61n2a3 |
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Uso de las Propiedades Fisicoquímicas de Oligonucleótidos como Biomarcadores
Use of oligonucleotid physicochemical properties as biomarkers
José Martínez Reyes1,* Eduardo González Partida1 y Renee J. Perez2
1 Centro de Geociencias, Universidad Nacional Autónoma de México, Campo de Juriquilla, Qro., México, apartado postal 76230.
2 Department of Chemical and Petroleum Engineering, University of Calgary, 500 University Drive, Calgary Alberta, Canada, T2N 1N4.
* This email address is being protected from spambots. You need JavaScript enabled to view it..
Abstract
Biological markers (biomarkers) are complex molecular fossils from biomolecules in living organisms. Due to their general are resistant to weather, the biodegradation, evaporation and other biological processes, as commonly preserved in rocks and can be used by geologists, geochemists, archaeologists, etc. for information on organic matter in source rocks, the presence of oil, environmental conditions during sedimentation (diagenetic process), the thermal maturity experienced by the oil and / or rock (catagenetic process), the degree of biodegradation, some aspects of mineralogy of the source rock (lithology), the age of fossils and characterization of DNA (deoxyribonucleic acid). Biomarkers can be oligonucleotides, which are stretches of DNA molecules of simple fixed–length string.
DNA from fossils can form cross–links among themselves or with other molecules to the passage of time, hindering the use of techniques such as PCR for study, therefore, in this work was applied to oligonucleotides a technique for determining the pKa values (potential of the ionization constant), by UVspectrophotometry in the basic pH range, using as the model oligonucleotide d–AAAGAAA in NaCl aqueous solution, titrating it with NaOH solution. Also in the presence of a pH buffer solution (NaHCO3). Furthermore pKa values were determined for the same compound at different conditions of temperature, salts and mixtures of alcohol–water as solvent. We also assessed the pKa oligonucleotides d–CCCGCCC and d–AAGAA.
pKa values were obtained on a range between 9 and 12. These results are a contribution to the knowledge of the physical properties of oligonucleotides, such data may be particularly useful in the aforementioned case of difficulty using other techniques such as PCR for the characterization and interpretation of oligonucleotides as biomarkers.
Keywords: oligonucleotides, biomarkers, potential of ionization constants.
