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Bada, JL, Schoeninger MJ, Schimmelmann A.  1989.  Isotopic Fractionation During Peptide-Bond Hydrolysis. Geochimica Et Cosmochimica Acta. 53:3337-3341.   10.1016/0016-7037(89)90114-2   Website
Bada, JL, Zhao MX, Steinberg S, Ruth E.  1986.  Isoleucine Stereoisomers on the Earth. Nature. 319:314-316.   10.1038/319314a0   Website
Glavin, DP, Bada JL.  1998.  Isolation of amino acids from natural samples using sublimation. Analytical Chemistry. 70:3119-3122.   10.1021/ac9803784   AbstractWebsite

Amino acids have appreciable vapor pressures above 150 degrees C and will sublime under partial vacuum at elevated temperatures without any racemization or decomposition. The recoveries of several amino acids including aspartic acid, serine, glycine, alanine, ol-aminoisobutyric acid, and valine were optimized by varying the temperature and duration of sublimation. Sublimation has been shown to be a rapid and effective technique for the isolation of amino acids from natural samples for enantiomeric analyses and a good substitute for conventional cation-exchange desalting techniques.

Bada, JL, Chalmers JH, Cleaves HJ.  2016.  Is formamide a geochemically plausible prebiotic solvent? Physical Chemistry Chemical Physics. 18:20085-20090.   10.1039/c6cp03290g   AbstractWebsite

From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >= 20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 degrees C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that similar to 85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

Bada, JL.  1984.  Invivo Racemization in Mammalian Proteins. Methods in Enzymology. 106:98-115.Website
Boehm, MF, Bada JL.  1984.  Investigations of Invivo Methionine Racemization in Mammalian-Tissues. Biochemistry International. 8:603-608.Website
Keefe, AD, Miller SL, McDonald G, Bada J.  1995.  Investigation of the Prebiotic Synthesis of Amino-Acids and Rna Bases from Co2 Using Fes/H2s as a Reducing Agent. Proceedings of the National Academy of Sciences of the United States of America. 92:11904-11906.   10.1073/pnas.92.25.11904   AbstractWebsite

An autotrophic theory of the origin of metabolism and life has been proposed in which carbon dioxide is reduced by ferrous sulfide and hydrogen sulfide by means of a reversed citric acid cycle, leading to the production of amino acids. Similar processes hale been proposed for purine synthesis. Ferrous sulfide is a strong reducing agent in the presence of hydrogen sulfide and can produce hydrogen as web as reduce alkenes, alkynes, and thiols to saturated hydrocarbons and reduce ketones to thiols. However, the reduction of carbon dioxide has not been demonstrated. We show here that no amino acids, purines, or pyrimidines are produced from carbon dioxide with the ferrous sulfide and hydrogen sulfide system. Furthermore, this system does not produce amino acids from carboxylic acids by reductive amination and carboxylation. Thus, the proposed autotrophic theory, using carbon dioxide, ferrous sulfide, and hydrogen sulfide, lacks the robustness needed to be a geological process and is, therefore, unlikely to have played a role in the origin of metabolism or the origin of life.

Elsila, JE, Glavin DP, Dworkin JP, Martins Z, Bada JL.  2012.  Inconclusive evidence for nonterrestrial isoleucine enantiomeric excesses in primitive meteorites. Proceedings of the National Academy of Sciences of the United States of America. 109:E3288-E3288.   10.1073/pnas.1213261109   Abstract

Pizzarello et al. (1) recently described the soluble organic content of eight Antarctic Renazzo-type (CR) carbonaceous chondrites and reported large enantiomeric excesses (ee) of l-isoleucine and d-alloisoleucine. The reported values of ee decrease with inferred increases in aqueous alteration. We believe the conclusions presented in the paper are not fully justified and the data are potentially flawed.

Potential terrestrial contamination of meteoritic amino acid data must always be considered. The manuscript states that “terrestrial contamination levels… were evaluated based on the presence of proteinogenic amino acids’ l-excesses and accounted for when needed,” but this “accounting” is not described. A wide range of l-proteinogenic amino acid excesses was measured …

Bada, JL, Bigham C, Miller SL.  1994.  Impact Melting of Frozen Oceans on the Early Earth - Implications for the Origin of Life. Proceedings of the National Academy of Sciences of the United States of America. 91:1248-1250.   10.1073/pnas.91.4.1248   AbstractWebsite

Without sufficient greenhouse gases in the atmosphere, the early Earth would have become a permanently frozen planet because the young Sun was less luminous than it is today. Several resolutions to this faint young Sun-frozen Earth paradox have been proposed, with an atmosphere rich in CO2 being the one generally favored. However, these models assume that there were no mechanisms for melting a once frozen ocean. Here we show that bolide impacts between about 3.6 and 4.0 billion years ago could have episodically melted an ice-covered early ocean. Thaw-freeze cycles associated with bolide impacts could have been important for the initiation of abiotic reactions that gave rise to the first living organisms.