Matsuzawa T, Obara Y
Brain Res. 1987 Jun 16;413(2):314-9. doi: 10.1016/0006-8993(87)91022-5.
The regional distribution of proline biosynthetic enzymes, ornithine-delta-aminotransferase and delta 1-pyrroline-5-carboxylate reductase, in the rat brain, and basic conditions for proline synthesis from ornithine in rat and chicken brain slices and chicken retinas were investigated. The cerebral regions relating to memory formation and imprinting (cortex, hypothalamus and hippocampus) exhibited a high activity of ornithine-delta-aminotransferase, while delta 1-pyrroline-5-carboxylate reductase activity was ubiquitously high. Amino acids were determined fluorometrically after separation and reaction with o-phthaldialdehyde by high-performance liquid chromatography. Proline formation was both ornithine- and 2-oxoglutarate-dependent, and the proline level was suppressed by a high-potassium medium in the brain slices but not in the detached retinas. Its main precursor in vitro seemed to be ornithine but not arginine. The retinas from formoguanamine (2,4-diamino-S-triazine)-treated chicks showed a 10-fold higher level of proline and a marked decrease in gamma-aminobutyric acid, presumably due to an impairment of the blood-retina barrier. The different response in proline level to the high-potassium medium in the brain slices and detached neuroretinas suggests that cellular distribution of the enzymes relating to ornithine and proline metabolism is different in the brain and the neuroretina.
研究了脯氨酸生物合成酶——鸟氨酸-δ-氨基转移酶和δ1-吡咯啉-5-羧酸还原酶在大鼠脑中的区域分布，以及大鼠和鸡脑切片及鸡视网膜中由鸟氨酸合成脯氨酸的基本条件。与记忆形成和印记相关的脑区（皮层、下丘脑和海马体）表现出较高的鸟氨酸-δ-氨基转移酶活性，而δ1-吡咯啉-5-羧酸还原酶活性普遍较高。通过高效液相色谱法分离并与邻苯二甲醛反应后，用荧光法测定氨基酸。脯氨酸的形成既依赖于鸟氨酸，也依赖于2-氧代戊二酸，并且在脑切片中脯氨酸水平受到高钾培养基的抑制，但在分离的视网膜中不受影响。其体外主要前体似乎是鸟氨酸而非精氨酸。用甲酰胍胺（2,4-二氨基-S-三嗪）处理的雏鸡的视网膜显示脯氨酸水平高出10倍，γ-氨基丁酸显著减少，这可能是由于血视网膜屏障受损所致。脑切片和分离的神经视网膜中脯氨酸水平对高钾培养基的不同反应表明，与鸟氨酸和脯氨酸代谢相关的酶在脑和神经视网膜中的细胞分布不同。
