Reichmann H, Maltese W A, DeVivo D C
Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York.
J Neurochem. 1988 Aug;51(2):339-44. doi: 10.1111/j.1471-4159.1988.tb01044.x.
Developmental profiles were determined for the activities of eight enzymes involved in fatty acid beta-oxidation in rat brain. The enzymes studied were the palmitoyl-CoA, octanoyl-CoA, butyryl-CoA, glutaryl-CoA, and 3-hydroxyacyl-CoA dehydrogenases, the enoyl-CoA hydratase (crotonase), and the C4- and C10-thiolases. With the exception of the thiolases, all of the activities (expressed on the basis of brain weight) increased during the postnatal period of brain maturation. The activity of octanoyl-CoA dehydrogenase was elevated markedly compared to that of palmitoyl-CoA dehydrogenase at all developmental stages and in all brain regions in the rat. A similar relationship between these enzymes was observed in various regions of adult human brain. Comparisons of the activities of the beta-oxidation enzymes in human brain versus human skeletal muscle and in cultured neural cell lines (neuroblastoma and glioma) versus cultured skin fibroblasts revealed that the elevated activity of octanoyl-CoA dehydrogenase relative to palmitoyl-CoA dehydrogenase was specific to the neural tissues. This relationship was particularly evident when the enzyme activities were normalized to the activity of crotonase. The data support previous findings with radiochemical tracers, indicating that the brain is capable of utilizing fatty acids as substrates for oxidative energy metabolism. The relatively high activity of the medium-chain fatty acyl-CoA dehydrogenase in neural tissue may represent an adaptive mechanism to protect the brain from the known encephalopathic effects of octanoate and other medium-chain fatty acids that readily cross the blood-brain barrier.
测定了大鼠脑中参与脂肪酸β-氧化的八种酶的活性发育情况。所研究的酶包括棕榈酰辅酶A、辛酰辅酶A、丁酰辅酶A、戊二酰辅酶A和3-羟酰基辅酶A脱氢酶、烯酰辅酶A水合酶（巴豆酸酶）以及C4-和C10-硫解酶。除硫解酶外，所有活性（以脑重量为基础表示）在脑成熟的出生后阶段均增加。在大鼠的所有发育阶段和所有脑区，辛酰辅酶A脱氢酶的活性均显著高于棕榈酰辅酶A脱氢酶。在成人大脑的各个区域也观察到了这些酶之间的类似关系。比较人脑与人体骨骼肌以及培养的神经细胞系（神经母细胞瘤和胶质瘤）与培养的皮肤成纤维细胞中β-氧化酶的活性，发现辛酰辅酶A脱氢酶相对于棕榈酰辅酶A脱氢酶活性升高是神经组织特有的。当酶活性以巴豆酸酶的活性进行标准化时，这种关系尤为明显。这些数据支持了先前使用放射性化学示踪剂的研究结果，表明大脑能够利用脂肪酸作为氧化能量代谢的底物。神经组织中中链脂肪酰辅酶A脱氢酶的相对高活性可能代表一种适应性机制，以保护大脑免受已知的辛酸和其他容易穿过血脑屏障的中链脂肪酸的脑病作用。
