Dienel G, Ryder E, Greengard O
Biochim Biophys Acta. 1977 Feb 28;496(2):484-94. doi: 10.1016/0304-4165(77)90330-0.
The subcellular distribution of mitochondrial enzymes was studied in cerebral hemispheres of 15-day-old and adult rats. At both ages the synaptosomal fraction contained very little glutamate dehydrogenase (EC 1.4.1.2) but significant amounts of succinate dehydrogenase (EC 1.3.99.1), glutaminase (EC 3.5.1.2), hexokinase (EC 2.7.1.1), malate NADP dehydrogenase (EC 1.1.1.40) and beta-hydroxybutyrate dehydrogenase (EC 1.1.1.30). In immature brain, in the fraction enriched with free (perikaryal) mitochondria, the concentrations of these enzymes were 9.5, 1.8, 2.0, 0.92, 1.5, and 2.1 times higher, respectively, than in the synaptosomes. The increase with age in succinate dehydrogenase and glutaminase was restricted to free mitochondria while hexokinase and malate NADP dehydrogenase accumulated and beta-hydroxybutyrate dehydrogenase diminished in both fractions. In adult brain, too, where the above ratios became 7.5, 5.2, 3.5, 0.84, 1.4, and 2.0, respectively, the concentrations of enzymes relative to each other distinguished clearly between free and synaptic mitochondria. The results substantiate previously noted signs of mitochondrial heteroeneity in adult brain, and extend them to immature brain. The chemical composition, the quantitative pattern of enzymes, of free and synaptic mitochondria is clearly different, and undergoes separate changes during postnatal differentiation.
研究了15日龄和成年大鼠大脑半球中线粒体酶的亚细胞分布。在这两个年龄段，突触体部分所含的谷氨酸脱氢酶（EC 1.4.1.2）很少，但含有大量的琥珀酸脱氢酶（EC 1.3.99.1）、谷氨酰胺酶（EC 3.5.1.2）、己糖激酶（EC 2.7.1.1）、苹果酸NADP脱氢酶（EC 1.1.1.40）和β-羟丁酸脱氢酶（EC 1.1.1.30）。在未成熟的大脑中，富含游离（胞体）线粒体的部分中，这些酶的浓度分别比突触体中的高9.5、1.8、2.0、0.92、1.5和2.1倍。琥珀酸脱氢酶和谷氨酰胺酶随年龄的增加仅限于游离线粒体，而已糖激酶和苹果酸NADP脱氢酶在两个部分中都有积累，β-羟丁酸脱氢酶则减少。在成体大脑中，上述比例分别变为7.5、5.2、3.5、0.84、1.4和2.0，游离线粒体和突触线粒体中酶的相对浓度也有明显差异。这些结果证实了先前在成体大脑中观察到的线粒体异质性迹象，并将其扩展到未成熟大脑。游离线粒体和突触线粒体的化学成分、酶的定量模式明显不同，并且在出生后分化过程中发生各自的变化。
