Guionie Olivier, Clottes Eric, Stafford Kirsten, Burchell Ann
Ninewells Hospital and Medical School, University of Dundee, DD1 9SY Dundee, UK.
FEBS Lett. 2003 Sep 11;551(1-3):159-64. doi: 10.1016/s0014-5793(03)00903-7.
The liver endoplasmic reticulum glucose-6-phosphatase catalytic subunit (G6PC1) catalyses glucose 6-phosphate hydrolysis during gluconeogenesis and glycogenolysis. The highest glucose-6-phosphatase activities are found in the liver and the kidney; there have been many reports of glucose 6-phosphate hydrolysis in other tissues. We cloned a new G6Pase isoform (G6PC3) from human brain encoded by a six-exon gene (chromosome 17q21). G6PC3 protein was able to hydrolyse glucose 6-phosphate in transfected Chinese hamster ovary cells. The optimal pH for glucose 6-phosphate hydrolysis was lower and the K(m) higher relative to G6PC1. G6PC3 preferentially hydrolyzed other substrates including pNPP and 2-deoxy-glucose-6-phosphate compared to the liver enzyme.
肝脏内质网葡萄糖-6-磷酸酶催化亚基（G6PC1）在糖异生和糖原分解过程中催化6-磷酸葡萄糖水解。葡萄糖-6-磷酸酶活性最高的部位是肝脏和肾脏；其他组织中也有许多关于6-磷酸葡萄糖水解的报道。我们从人脑中克隆了一种新的G6Pase同工型（G6PC3），它由一个含六个外显子的基因（染色体17q21）编码。G6PC3蛋白能够在转染的中国仓鼠卵巢细胞中水解6-磷酸葡萄糖。相对于G6PC1，6-磷酸葡萄糖水解的最适pH较低，米氏常数（K(m)）较高。与肝脏中的酶相比，G6PC3优先水解包括对硝基苯磷酸酯（pNPP）和2-脱氧-6-磷酸葡萄糖在内的其他底物。
