Carboxyl affinity chromatography

Recombinant DNA technology can also be used to create modified proteins that are readily purified by affinity chromatography. The gene of interest is Unked to an oligonucleotide sequence that encodes a carboxyl or amino terminal extension to the encoded protein. The... 

Elimination of coextracted materials and concentration of tetracyclines have also been accomplished using mixed-phase extraction membranes with both re-versed-phase and cation-exchange properties (294,295), or solid-phase extraction columns packed with cation-exchange materials such as CM-Sephadex C-25 (301), aromatic sulfonic acid (310), and carboxylic acid (283, 300). For the same purpose, metal chelate affinity chromatography has also been employed. In this technique, the tetracyclines are specifically absorbed on the column sorbent by chelation with copper ions bound to small chelating Sepharose fast flow column (278-281, 294-296). 

Combining affinity chromatography, two-dimensional electrophoresis, and mass spectroscopy, Becamel and colleagues pioneered a global proteomic approach to 5-HT receptosomes (Chapter 7). These groundbreaking studies employed either the entire or partial carboxyl terminus of the 5-HT2 receptors as bait and heralded the discovery of multiple FRAPs (14,15). Since then, the proteomic strategy has been successfully applied to other 5-HT receptor subtypes (16,17). 

It is also possible to determine the level of metabolites in urine. Urinary 2-thiothiazolidine-4-carboxylic acid is the best available indicator to assess the degree of occupational exposure to carbon disulfide (ACGIH 1994 Theinpont et al. 1990). Theinpont et al. (1990) described the isolation of this compound from urine prior to reverse phase high-performance liquid chromatography. It is based on liquid-liquid extraction with methyl tertbutyl ether, followed by affinity chromatography on organomercurial agarose gel. The detection limit of the procedure was 50 g of carbon disulfide/L of urine (Theinpont et al. 1990). 

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