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Science 31 July 1981:
Vol. 213. no. 4507, pp. 544 - 545
DOI: 10.1126/science.213.4507.544
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Articles

Diketopiperazine Formation During Investigations of Amino Acid Racemization in Dipeptides

SPENCER STEINBERG 1 and JEFFREY L. BADA 1

1 Amino Acid Dating Laboratory, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093

The formation of diketopiperazines from the dipeptides isoleucylglycine and glycylisoleucine was investigated at 132°C over the pH range sim 2 to 10. At pH 6.2, sim 50 percent of the original dipeptides were converted to the diketopiperazines during the heating experiments. Hydrolysis of the diketopiperazines can yield either the original dipetide or an inverted dipeptide product. The isoleucine in the diketopiperazines was the most highly epimerized component in the system. Previous racemization and epimerization studies with dipeptides have not taken into account the formation of diketopiperazines and, as a result, the cortclusions about the mechanism and geochemical implications of amino acid racemization in dipeptides will require revision.

Submitted on January 13, 1981
Revised on April 7, 1981


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Invited Review: Dipeptides in Parenteral Nutrition: From Basic Science to Clinical Applications.
J. A. Vazquez, H. Daniel, and S. A. Adibi (1993)
Nutr Clin Pract 8, 95-105
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