Blachier F, M'Rabet-Touil H, Darcy-Vrillon B, Posho L, Duee P H
Laboratoire d'Ecologie et de Physiologie du Système Digestif, Institut National de la Recherche Agronomique, JOUY-en-JOSAS, France.
Biochem Biophys Res Commun. 1991 Jun 28;177(3):1171-7. doi: 10.1016/0006-291x(91)90663-r.
In enterocytes isolated from pig jejunum, L-arginine is metabolized to L-citrulline either directly or indirectly through the sequence of reactions catalysed by arginase and ornithine transcarbamylase. In the presence of 5 mM D-glucose, the direct conversion of 1mM L-[guanido-14C] arginine to L-citrulline was increased more than 4 times. Isolated enterocytes exhibit a high glycolytic capacity. Furthermore, the decarboxylation of 5mM D-[1-14C] glucose was 3.6 fold higher than the decarboxylation of 5 mM D-[6-14C] glucose which suggests the presence of a pentose phosphate pathway in enterocytes. Since the production of labelled L-citrulline from L-[guanido-14C] arginine in pig enterocyte homogenates was markedly increased in the presence of NADPH, it is proposed that the direct conversion of L-arginine to L-citrulline could be stimulated by the production of NADPH from D-glucose in the pentose phosphate pathway.
在从猪空肠分离出的肠上皮细胞中，L-精氨酸可直接或通过精氨酸酶和鸟氨酸转氨甲酰酶催化的反应序列间接代谢为L-瓜氨酸。在5 mM D-葡萄糖存在的情况下，1 mM L-[胍基-14C]精氨酸向L-瓜氨酸的直接转化增加了4倍多。分离出的肠上皮细胞表现出较高的糖酵解能力。此外，5 mM D-[1-14C]葡萄糖的脱羧作用比5 mM D-[6-14C]葡萄糖的脱羧作用高3.6倍，这表明肠上皮细胞中存在磷酸戊糖途径。由于在NADPH存在的情况下，猪肠上皮细胞匀浆中L-[胍基-14C]精氨酸产生标记的L-瓜氨酸的量显著增加，因此有人提出，磷酸戊糖途径中D-葡萄糖产生的NADPH可刺激L-精氨酸向L-瓜氨酸的直接转化。
