Summary
The pathway of gluconeogenesis from pyruvate, lactate and alanine was investigated in isolated liver cells of the eel. Amino-oxyacetate, a transaminase inhibitor, inhibited gluconeogenesis not only from lactate, but also from pyruvate by 60%.d-Malate did not inhibit gluconeogenesis from either of the substrates (Table 1 A).
The effects of various amino acids on gluconeogenesis were investigated. Leucine accelerated gluconeogenesis from pyruvate or alanine (Table 2). Leucine promoted the incorporation of14C-pyruvate into glutamate and aspartate, and increased the glutamate content. The specific activity of14C-aspartate was increased markedly by leucine (Table 5).
From the investigation of subcellular distribution of enzymes unique to gluconeogenesis, it was found that pyruvate carboxylase was located almost exclusively in the mitochondrial fraction, and that phophoenolpyruvate carboxykinase and aspartate transaminase were located in both the mitochondrial and the cytosolic fractions (Table 7).
From these results it is concluded that the oxaloacetate-aspartate pathway is a major route in gluconeogenesis from any of the substrates in the eel liver.
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Abbreviations
- AOA :
-
amino-oxyacetate
- PEP :
-
phosphoenolpyruvate
References
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