TY - JOUR
T1 - Properties and Subcellular Localization of Myocardial Fatty Acyl-coenzyme A Oxidase
AU - Harrison, Earl H.
AU - Walusimbi, Mbaga S.
PY - 1988/9/1
Y1 - 1988/9/1
N2 - The properties and subcellular localization of fatty acyl-CoA oxidase (FAO) were studied in rat heart homogenates. After differential centrifugation, FAO was sedimentable and enriched in a “light-mitochondrial” fraction. FAO had a pH optimum of 8–9. Among straight-chain, saturated fatty acyl-CoAs, the enzyme showed a marked preference for medium chain substrates (C 12 > C 10 = C8 > C 16 = C 14 > C 6 ) over a concentration range up to 100 µM. No activity was observed with C 4 -CoA. The apparent Michaelis constant (K m ) for C 12 -CoA was 5-10 µM. After removal of nuclei by low-speed centrifugation, combined subcellular particle preparations were obtained by high-speed centrifugation and layered on linear density gradients of metrizamide. After density equilibration, FAO showed a symmetric distribution centered at ρ = 1.16–1.18, like that of the enzyme catalase, a marker for microperoxisomes. In contrast, enzyme markers for mitochondria, lysosomes, sarcolemma, and sarcoplasmic reticulum were recovered in low-density regions of the gradient. These results provide a direct demonstration of fatty acyl-CoA oxidase in cardiac tissue and its association with microperoxisomes.
AB - The properties and subcellular localization of fatty acyl-CoA oxidase (FAO) were studied in rat heart homogenates. After differential centrifugation, FAO was sedimentable and enriched in a “light-mitochondrial” fraction. FAO had a pH optimum of 8–9. Among straight-chain, saturated fatty acyl-CoAs, the enzyme showed a marked preference for medium chain substrates (C 12 > C 10 = C8 > C 16 = C 14 > C 6 ) over a concentration range up to 100 µM. No activity was observed with C 4 -CoA. The apparent Michaelis constant (K m ) for C 12 -CoA was 5-10 µM. After removal of nuclei by low-speed centrifugation, combined subcellular particle preparations were obtained by high-speed centrifugation and layered on linear density gradients of metrizamide. After density equilibration, FAO showed a symmetric distribution centered at ρ = 1.16–1.18, like that of the enzyme catalase, a marker for microperoxisomes. In contrast, enzyme markers for mitochondria, lysosomes, sarcolemma, and sarcoplasmic reticulum were recovered in low-density regions of the gradient. These results provide a direct demonstration of fatty acyl-CoA oxidase in cardiac tissue and its association with microperoxisomes.
UR - https://corescholar.libraries.wright.edu/surg/190
UR - http://ajpheart.physiology.org/content/255/3/H441.long
M3 - Article
VL - 255
JO - American Journal of Physiology
JF - American Journal of Physiology
ER -