title: Stability of long-chain and short-chain 3-hydroxyacyl-CoA dehydrogenase activity in postmortem liver.
abstract: Inherited enzyme defects in mitochondrial fatty acid oxidation (FAO) are associated with acute metabolic crisis and sudden death. Necropsy findings may be subtle, yielding no diagnosis and precluding genetic counseling. Preliminary identification of an FAO disorder requires the use of sophisticated tools (e.g., GC/MS) and specific body fluids, and the diagnosis rests on molecular analysis or enzyme assay. At present, confirmation of long-chain or short-chain 3-hydroxyacyl-CoA dehydrogenase deficiency relies on measurement of enzyme activity. Here, we report our examination of the effect of storage temperature (25, 4, -20, and -70 degrees C) and the postmortem interval on enzyme activities in rat and human liver. Enzyme activity decreases 50% in 30 h in samples stored at 25 degrees C, whereas 55 h at 4 degrees C is required to reach this value; freezing minimizes this loss. Regardless of rate of degradation, however, the short-chain to long-chain activity ratio remains constant--which should make it possible to differentiate postmortem degradation from enzyme deficiency.
authors.affiliation: Department of Pediatrics, University of Texas Health Science Center at San Antonio, 78284, USA. hale@uthscsa.edu
authors.forename: D E
authors.initials: DE
authors.lastname: Hale
authors.forename: J E
authors.initials: JE
authors.lastname: Cornell
authors.forename: M J
authors.initials: MJ
authors.lastname: Bennett
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000172:deficiency / Q000378:metabolism*; D000818:Animals; D004795:Enzyme Stability; D005615:Freezing; D006801:Humans; D007223:Infant; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D008297:Male; D011180:Postmortem Changes; D051381:Rats; D017207:Rats, Sprague-Dawley; D013398:Sudden Infant Death / Q000175:diagnosis
chemical_list: D015094:3-Hydroxyacyl CoA Dehydrogenases