Carter C J
Life Sci. 1983 Apr 25;32(17):1949-55. doi: 10.1016/0024-3205(83)90046-2.
There is a linear negative correlation between the activities of glutamine synthetase and fructose-1, 6-diphosphatase in normal Human putamen autopsy samples, and also in the Huntington's disease putamen. However, glutamine synthetase activity is reduced in choreic brain samples, while fructose-1, 6-diphosphatase activity is normal. The ratio of fructose-1, 6-diphosphatase to glutamine synthetase is therefore increased in Huntington's disease. The products of the two reactions, glutamine and fructose-6-phosphate, are the starting substrates for glycolipid and glycoprotein biosynthesis, via the glutamine:fructose-6-phosphate aminotransferase catalysed formation of glucoseamine-6-phosphate. The alternative metabolic route of fructose-6-phosphate leads to glycogen. The availability of glutamine, and the activity of glutamine synthetase may control fructose-6-phosphate metabolism, and the increased ratio of fructose-1,6-diphosphatase to glutamine synthetase in Huntington's disease may explain the accumulation of glycogen, and the reduction in ganglioside levels reported in this state.
在正常人壳核尸检样本以及亨廷顿病患者的壳核中，谷氨酰胺合成酶与果糖-1,6-二磷酸酶的活性之间存在线性负相关。然而，在舞蹈病脑样本中，谷氨酰胺合成酶活性降低，而果糖-1,6-二磷酸酶活性正常。因此，在亨廷顿病中，果糖-1,6-二磷酸酶与谷氨酰胺合成酶的比值增加。这两个反应的产物，谷氨酰胺和果糖-6-磷酸，是通过谷氨酰胺：果糖-6-磷酸转氨酶催化生成葡糖胺-6-磷酸，进而用于糖脂和糖蛋白生物合成的起始底物。果糖-6-磷酸的另一条代谢途径则导致糖原生成。谷氨酰胺的可用性以及谷氨酰胺合成酶的活性可能控制果糖-6-磷酸的代谢，而亨廷顿病中果糖-1,6-二磷酸酶与谷氨酰胺合成酶比值的增加，可能解释了在这种疾病状态下糖原的积累以及神经节苷脂水平的降低。
