title: Long-chain acyl-CoA and acylcarnitine hydrolase activities in normal and ischemic rabbit heart.
abstract: Long-chain acyl-CoA and acylcarnitine hydrolase activities were determined in fresh and perfused rabbit heart and correlated with tissue levels of their respective substrates, long-chain acyl-CoA and acylcarnitine. In fresh heart homogenate acyl-CoA hydrolase activity was 3-fold greater than acylcarnitine hydrolase activity; sonication of homogenate doubled acyl-CoA hydrolase activity but did not significantly change acylcarnitine hydrolase activity. Hearts perfused with 10 mM glucose by the nonrecirculating Langendorff method had depressed levels of acyl-CoA hydrolase activity under both aerobic and ischemic conditions. Extract from buffer-perfused heart showed increased acylcarnitine hydrolase activity and elevated levels of acylcarnitine. Homogenate acyl-CoA hydrolase activity was not sedimented by centrifugal forces up to 50,000 X g; however, less than 25% of homogenate acylcarnitine hydrolase activity remained in the 50,000 X g supernatant. The hypolipidemic drug clofibrate was an effective in vitro inhibitor of acylcarnitine hydrolase activity but not of acyl-CoA hydrolase activity. The fatty acid analog tetradecylglycidic acid inhibited only acyl-CoA hydrolase activity. These results suggest that acyl-CoA hydrolase and acylcarnitine hydrolase activities are differentially affected in the perfused heart by substrate levels and oxygen availability. In addition, the diverse response of these two hydrolase activities to a variety of biochemical parameters implies that the observed hydrolyses of palmitoyl-CoA and palmitoylcarnitine are catalyzed by at least two separate hydrolase enzymes.
mesh_terms: D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000032:analysis* / Q000037:antagonists & inhibitors; D002994:Clofibrate / Q000494:pharmacology; D003327:Coronary Disease / Q000201:enzymology*; D004852:Epoxy Compounds / Q000494:pharmacology; D005227:Fatty Acids / Q000494:pharmacology; D008297:Male; D051379:Mice; D009206:Myocardium / Q000201:enzymology*; D010170:Palmitoyl-CoA Hydrolase / Q000032:analysis* / Q000037:antagonists & inhibitors; D011817:Rabbits; D051381:Rats; D013045:Species Specificity; D013869:Thiolester Hydrolases / Q000032:analysis*
chemical_list: D004852:Epoxy Compounds; D005227:Fatty Acids; D002265:Carboxylic Ester Hydrolases; C029629:palmitoyl-L-carnitine hydrolase; C019843:acylcarnitine hydrolase; D013869:Thiolester Hydrolases; D010170:Palmitoyl-CoA Hydrolase; D002994:Clofibrate; C021756:2-tetradecylglycidic acid