大豆・エンドウ発芽種子子葉のフォスフォエノールピルビン酸カルボキシラーゼの部分精製と性質について(貯蔵物質を異にする発芽種子のフォスフォエノールピルビン酸とオキザロ酢酸の間の反応を触媒する酵素についての研究-2-)

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The activity of phosphoenolpyruvate carboxylase (PEPC) of soybean cotyledon rapidl reduced with germination and that of pea cotyledon showed the maximum on the 5 th day after germination. The enzymes were extracted from the 3 rd day soybean cotyledon after germination and from the 5 th day pea cotyledon and purified partially, and some properties of both enzymes were studied. Optimum pH values of both enzymes were about 8.7 and they required Mg ion but not reductant for the activity. Km values for PEP and MgCl2 were 0.11mM and 0.095mm on PEPC from soybean, and 0.084mM and 0.071mM on PEPC from pea, respectively. Both enzymes were inhibited by citrate, isocitrate and nucleotides and pea enzyme was also inhibited by succinate. Consequently, both PEPC's were thought to have similar enzymatic properties. The physiological significance of PEPC of soybean might be difficult to consider, since the activity rapidly decreases after germination and the Km values for ligands are comparatively large. On the contrary, the PEPC of pea might have anaplerotic functions in metabolic regulation.
社団法人日本農芸化学会の論文