title: Intracellular localization and some properties of the system in guinea pig liver responsible for the aromatization of cyclohexanecarboxylic acid to hippuric acid.
abstract: The conversion of cyclohexanecarboxylic acid to hippuric acid in subcellular fractions from guinea pig liver was studied using a gas chromatographic-mass spectrometric method employing selected ion monitoring. Comparison of the activities of the cyclohexanecarboxylic acid to hippuric acid converting system (CHC-system) and marker enzymes in the various subcellular fractions showed that the CHC-system is localized exclusively in the mitochondria. No contribution to the total activity of the system was made by microsomal enzymes. The activity of the CHC-system in whole liver homogenate and in isolated mitochondria was similar when the latter were supplemented with ATP, alpha-ketoglutaric acid, glycine, ethylenediaminetetraacetate, PO4(3-) and Mg2+. The formation of hippuric acid in these mitochondrial preparations was linear with respect to time over a period of at least 60 min. Studies designed to optimize the incubation conditions showed that the activity of the CHC-system was reduced by PO4(3-) concentrations greater than approximately 70 mM. Conversely, both ATP and alpha-ketoglutaric acid stimulated the system. It is possible that two different types of acyl-CoA synthetases, one which is ATP-specific and one which is GTP-specific, may operate in the activation of cyclohexanecarboxylic acid.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D003509:Cyclohexanecarboxylic Acids / Q000378:metabolism*; D006168:Guinea Pigs; D006626:Hippurates / Q000378:metabolism*; D066298:In Vitro Techniques; D007656:Ketoglutaric Acids / Q000494:pharmacology; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism; D011506:Proteins / Q000494:pharmacology; D013395:Sucrose / Q000494:pharmacology
chemical_list: D003509:Cyclohexanecarboxylic Acids; D006626:Hippurates; D007656:Ketoglutaric Acids; D011506:Proteins; D013395:Sucrose; D000255:Adenosine Triphosphate; C044895:cyclohexanecarboxylic acid; D008274:Magnesium; C030514:hippuric acid