Rozanov V A, Abu Asali I I, Rozanov A Ia
Ukr Biokhim Zh (1978). 1990 Sep-Oct;62(5):61-7.
Proceeding from estimation of the 14CO2 release from [5-14C]alpha-ketoglutarate, [1-14C] gamma-aminobutyric acid (GABA), [1,4-14C] succinate and [4-14C] aspartate (0.4-1 mM) during their incubation with homogenates of different brain areas with regard for the label position and stereospecificity of decarboxylation of citrate formed due to the metabolism, the relative intensity of their catabolism is determined: [1,4-14C] succinate much greater than [4-14C]aspartate greater than [5-14C] alpha-ketoglutarate much greater than [1-14C]GABA. The label release with catabolism of [1-14C] alpha-ketoglutarate considerably exceeds the intensity of decarboxylation of the above enumerated substrates. In all cases the maximum release of 14CO2 has been registered in the cortex homogenates, the minimum--in the medulla homogenates, and only under long-term incubation with high concentration of GABA (50 mM) maximum catabolism was registered in the medulla. Preincubation of nervous tissue with pyridoxal-5'-phosphate (40 microM) results in significant acceleration of catabolism of [1-14C] alpha-ketoglutarate, [5-14C] alpha-ketoglutarate and [4-14C] aspartate with an inconsiderable increase of catabolism of the rest of labelled substrates.
根据[5-¹⁴C]α-酮戊二酸、[1-¹⁴C]γ-氨基丁酸（GABA）、[1,4-¹⁴C]琥珀酸和[4-¹⁴C]天冬氨酸（0.4 - 1 mM）与不同脑区匀浆孵育过程中¹⁴CO₂的释放量估计，同时考虑到代谢产生的柠檬酸脱羧的标记位置和立体特异性，确定了它们分解代谢的相对强度：[1,4-¹⁴C]琥珀酸远大于[4-¹⁴C]天冬氨酸大于[5-¹⁴C]α-酮戊二酸远大于[1-¹⁴C]GABA。[1-¹⁴C]α-酮戊二酸分解代谢的标记释放量大大超过上述底物的脱羧强度。在所有情况下，¹⁴CO₂的最大释放量记录在皮质匀浆中，最小释放量记录在延髓匀浆中，并且只有在高浓度GABA（50 mM）长期孵育下，延髓中才记录到最大分解代谢。用磷酸吡哆醛（40 μM）对神经组织进行预孵育会导致[1-¹⁴C]α-酮戊二酸、[5-¹⁴C]α-酮戊二酸和[4-¹⁴C]天冬氨酸的分解代谢显著加速，而其余标记底物的分解代谢仅略有增加。
