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<h2>Extraterrestrial amino acids in Orgueil and Ivuna: Tracing the parent body of CI type carbonaceous chondrites </h2> <strong>Pascale Ehrenfreund<sup></sup><sup>,</sup><a href="http://www.pnas.org/cgi/content/full/98/5/2138?maxtoshow=&HITS=&hits=&RESULTFORMAT=1&fulltext=astrobiology&andorexactfulltext=and&searchid=1&FIRSTINDEX=50&resourcetype=HWCIT#FN151"><sup><img alt="dagger" src="http://www.pnas.org/math/12pt/normal/link/dagger.gif"></sup></a>, Daniel P. Glavin<sup><img alt="Dagger" src="http://www.pnas.org/math/12pt/normal/Dagger.gif"></sup>, Oliver Botta<sup><img alt="Dagger" src="http://www.pnas.org/math/12pt/normal/Dagger.gif"></sup>, George Cooper<sup>§</sup>, and Jeffrey L. Bada<a href="http://www.pnas.org/cgi/content/full/98/5/2138?maxtoshow=&HITS=&hits=&RESULTFORMAT=1&fulltext=astrobiology&andorexactfulltext=and&searchid=1&FIRSTINDEX=50&resourcetype=HWCIT#FN151"><sup><img alt="dagger" src="http://www.pnas.org/math/12pt/normal/link/dagger.gif"></sup></a><sup>,</sup><sup><img alt="Dagger" src="http://www.pnas.org/math/12pt/normal/Dagger.gif"></sup></strong> <p><em><sup></sup> Raymond and Beverly Sackler Laboratory for Astrophysics at Leiden Observatory, P.O. Box 9513, 2300 RA, Leiden, The Netherlands; <sup><img alt="Dagger" src="http://www.pnas.org/math/12pt/normal/Dagger.gif"></sup> Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212B; and <sup>§</sup> National Aeronautics and Space Administration AMES Research Center, Exobiology Branch, P.O. Box 204, Moffett Field, CA 94035 </em></p> <p><em>Edited by Donald E. Brownlee, University of Washington, Seattle, WA, and approved December 29, 2000 (received for review October 23, 2000)</em> </p> <a></a><br><a></a> <p>Amino acid analyses using HPLC of pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna have found that <img alt="beta" src="http://www.pnas.org/math/12pt/normal/beta.gif">-alanine, glycine, and <img alt="gamma" src="http://www.pnas.org/math/12pt/normal/gamma.gif">-amino-<em>n</em>-butyric acid (ABA) are the most abundant amino acids in these two meteorites, with concentrations ranging from <img alt="approx" src="http://www.pnas.org/math/12pt/normal/ap.gif">600 to 2,000 parts per billion (ppb). Other <img alt="alpha" src="http://www.pnas.org/math/12pt/normal/alpha.gif">-amino acids such as alanine, <img alt="alpha" src="http://www.pnas.org/math/12pt/normal/alpha.gif">-ABA, <img alt="alpha" src="http://www.pnas.org/math/12pt/normal/alpha.gif">-aminoisobutyric acid (AIB), and isovaline are present only in trace amounts ( isotopic measurements of <img alt="beta" src="http://www.pnas.org/math/12pt/normal/beta.gif">-alanine and glycine and the presence of racemic (D/L <img alt="approx" src="http://www.pnas.org/math/12pt/normal/ap.gif"> 1) alanine and <img alt="beta" src="http://www.pnas.org/math/12pt/normal/beta.gif">-ABA in Orgueil suggest that these amino acids are extraterrestrial in origin. In comparison to the CM carbonaceous chondrites Murchison and Murray, the amino acid composition of the CIs is strikingly distinct, suggesting that these meteorites came from a different type of parent body, possibly an extinct comet, than did the CM carbonaceous chondrites. </p> <p><em>PNAS February 27, 2001 vol. 98 no. 5 p 2138-2141.</em></p>
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