Racemization, amino acid

Enzymatic hydrolysis is also used for the preparation of L-amino acids. Racemic D- and L-amino acids and their acyl-derivatives obtained chemically can be resolved enzymatically to yield their natural L-forms. Aminoacylases such as that from Pispergillus OTj e specifically hydrolyze L-enantiomers of acyl-DL-amino acids. The resulting L-amino acid can be separated readily from the unchanged acyl-D form which is racemized and subjected to further hydrolysis. Several L-amino acids, eg, methionine [63-68-3], phenylalanine [63-91-2], tryptophan [73-22-3], and valine [72-18-4] have been manufactured by this process in Japan and production costs have been reduced by 40% through the appHcation of immobilized cell technology (75). Cyclohexane chloride, which is a by-product in nylon manufacture, is chemically converted to DL-amino-S-caprolactam [105-60-2] (23) which is resolved and/or racemized to (24)... [Pg.311]

Amino acid racemization (Section 27.2) A method for dating archeological samples based on the rate at which the stereochemistry at the a carbon of amino acid components is randomized. It is useful for samples too old to be reliably dated by decay. [Pg.1276]

Child, A.M., Gillard, R.D. and Pollard, A.M. 1993 Microbially-induced promotion of amino acid racemization in bone isolation of the microorganisms and the detection of their enzymes. Journal of Archaeological Science 20 159-168. [Pg.157]

Harmon RS, Mitterer RM, Kriausakul N, Land LS, Schwarcz HP, Garrett P, Larson GJ, Vacher HL, Rowe M (1983) U-Series and amino-acid racemization geochronology of Bermuda Implications for eustatic sea-level fluctrration over the past 250,000 years. Palaeogeog Palaeoclim Palaeoecol 44 41-70 Harmon RS, Schwarcz HP (1981) Changes of H and 0 errrichment of meteoric water and Pleistocene glaciation. Natrrre 290 125-128... [Pg.455]

DATING ANCIENT PROTEINS - AMINO ACID RACEMIZATION DATING... [Pg.363]

FIGURE 88 Dating methods. Shortly after the discovery of radioactivity, at the beginning of the twentieth century, it was found that the decay of radioactive elements could be used to keep track of time. Many of the dating techniques developed since then are, therefore, based on radioactive decay phenomena, but others, such as the hydration of obsidian, amino acid racemization, and dendrochronology, are based on other physical, chemical, or biological phenomena. [Pg.475]

AAR dating Abbreviation for amino acid racemization dating. [Pg.480]

Bada, J. L. (1985), Amino acid racemization dating of fossil bones, Ann. Rev. Earth Planet. Sci. 13, 241-268. [Pg.557]

Rutter, N. W. and B. Blackwell (1995), Amino acid racemization dating, in Rutter, N. W. and N. R. Catto (eds.), Dating Methods for Quaternary Deposits, Vol. 2, Geological Association of Canada, Geotext, St. John s, Newfoundland, pp. 125-164. [Pg.610]

BJ. Jonson, G.H. Miller, Archaeological applications of amino acid racemization, Archaeometry, 39, 265 2872 (1997). [Pg.29]

D. Kaufman, Dating Deep Lake Sediments by Using Amino Acid Racemization in Fossil Ostracodes, Geology, 31, 1049 1052 (2003). [Pg.258]

J. Robins, M. Jones, E. Matisoo Smith, Amino Acid Racemization Dating in New Zealand An Overview, Auckland University (2001). [Pg.259]

Bada, J. L., Shou, M., Effects of various environmental parameters on amino acid racemization rates in fossil bones, Geological Soc. America, Abstracts with Programs, 8, 762-763... [Pg.224]

Bada, J. L., Schroeder, R. A., Amino Acid Racemization Reactions and Their Geochemical Implications, Die Naturwessen-schaften, 1975, 62, 71-79. [Pg.467]

Bada, J. L., Master, P. M., Hoopes, E., Darling, The Dating of Fossil Bones Using Amino Acid Racemization, In Radiocarbon Dating, pp. 740-756, Berkeley, University of California Press, 1979. [Pg.467]

Bender, M. L., Reliability of Amino Acid Racemization Dating and Paleotemperature Analysis on Bones, Nature, 1974, 252, 378-379. [Pg.467]

Amino acid duplications, in sulfonamide resistance, 23 505 Amino acid inhibitors, 13 300-302 Amino acid racemization dating, 5 752 Amino acid residues, 9 494 26 376 Amino acids, 2 554-618 20 447 achiral derivatizing agents, 6 96t analysis, 2 596-600 analysis in green coffee, 7 253t analysis in roasted, brewed, and instant coffee, 7 255t... [Pg.47]

AMINO ACID RACEMIZATION DATING OF THE CALIFORNIAN PALEOINDIANS... [Pg.280]

SOME KIND OF JOKE CURRENT USES OF AMINO ACID RACEMIZATION... [Pg.289]

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See also in sourсe #XX -- [ Pg.1116 ]

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