Rognstad R, Wals P, Katz J
J Biol Chem. 1975 Nov 25;250(22):8642-6.
Glucose formed from [5-T]fructose in rat hepatocytes contains about 10 to 30% tritium. This does not appear to be due to fructose metabolism via hexokinase since neither the initial presence of glucose, nor wide variations in the original fructose concentration, have much effect on the relative labeling of glucose versus water from [5-T]fructose. Comparison of the T:14C ratios in glucose produced from [U-14C, 5-T]fructose and D-[U-14C, 2-T]glyceraldehyde indicate that there is tritium retention in the metabolism of fructose via the fructokinase-initiated pathway. The tritium retention can cause significant errors in the estimation of the futile cycle between fructose-1,6-P2 and fructose 6-P, by methods involving the use of [5-T]glucose.
在大鼠肝细胞中，由[5-T]果糖生成的葡萄糖含有约10%至30%的氚。这似乎并非由于果糖通过己糖激酶进行代谢，因为无论是最初存在的葡萄糖，还是原始果糖浓度的大幅变化，对[5-T]果糖生成的葡萄糖与水的相对标记影响都不大。比较由[U-14C, 5-T]果糖和D-[U-14C, 2-T]甘油醛生成的葡萄糖中的T:14C比率表明，在通过果糖激酶启动的途径进行的果糖代谢过程中存在氚保留。氚保留会在通过使用[5-T]葡萄糖的方法估算果糖-1,6-二磷酸和果糖6-磷酸之间的无效循环时导致显著误差。
