This paper describes the application of stereoselective antibodies as tailor-made chiral selectors for the separation of enantiomers in HPLC under isocratic conditions. Stereoselective monoclonal antibodies to D- and L-alpha-amino acids, raised against protein conjugates of p-amino-D- and L-phenylalanine, were immobilized on a synthetic high-flow-through support material and used for rapid enantiomer separation of a number of amino acids at flow rates between 0.1 and 10 mL/min. Since separations could be performed in a mild buffer, column lifetime considerably exceeded that of classical immunoaffinity systems. Using an anti-D-amino acid antibody as chiral selector, the L-enantiomers eluted with the void volume, while the D-enantiomers eluted second. Inverted elution orders were obtained on chiral stationary phases prepared from an anti-L-amino acid antibody. These results demonstrate, for the first time, that antibody-based chiral stationary phases are useful for routine enantiomer separation under true high-performance chromatographic conditions.
"Sixth, because of the exquisite flexibility and virtually unlimited nature of Ab-Ag interactions, it is possible to make antibodies against epitopes that do not occur naturally on Earth but could conceivably be incorporated by other life forms (Hofstetter et al., 1999). For example, while non-synthetic proteins consist of L-enantiomers of amino acids (Bada, 1985), antibodies can be raised against peptides consisting of D-enantiomers (Hofstetter et al., 2002; Vandenabeele-Trambouze et al., 2002), to test whether life on other planets exhibits varied chemical " handedness . " (Some organisms possess isomerase enzymes that, after synthesis, will racemize some amino acids to the D-isomer.) "
[Show abstract][Hide abstract] ABSTRACT: We propose a three-phase approach to test for evidence of life in extraterrestrial samples. The approach capitalizes on the flexibility, sensitivity, and specificity of antibody-antigen interactions. Data are presented to support the first phase, in which various extraction protocols are compared for efficiency, and in which a preliminary suite of antibodies are tested against various antigens. The antigens and antibodies were chosen on the basis of criteria designed to optimize the detection of extraterrestrial biomarkers unique to living or once-living organisms.
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