Glutamine synthetase and fructose-1, 6-diphosphatase activity in the putamen of control and Huntington's disease brain post mortem.
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.
D006597:Fructose-Bisphosphatase / Q000378:metabolism*; D005636:Fructosephosphates / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D005973:Glutamine / Q000378:metabolism; D006801:Humans; D006816:Huntington Disease / Q000201:enzymology*; D011699:Putamen / Q000201:enzymology*
D005636:Fructosephosphates; D005973:Glutamine; C027618:fructose-6-phosphate; D006597:Fructose-Bisphosphatase; D005974:Glutamate-Ammonia Ligase