Davies D R, Detheux M, Van Schaftingen E
Laboratoire de Chimie physiologique, International Institute of Cellular and Molecular Pathology, Brussels, Belgium.
Eur J Biochem. 1990 Sep 11;192(2):283-9. doi: 10.1111/j.1432-1033.1990.tb19225.x.
Fructose 1-phosphate kinase was partially purified from Clostridium difficile and used to develop specific assays of fructose 1-phosphate and fructose. The concentration of fructose 1-phosphate was below the detection limit of the assay (25 pmol/mg protein) in hepatocytes incubated in the presence of glucose as sole carbohydrate. Addition of fructose (0.05-1 mM) caused a concentration-dependent and transient increase in the fructose 1-phosphate content. Glucagon (1 microM) and ethanol (10 mM) caused a severalfold decrease in the concentration of fructose 1-phosphate in cells incubated with fructose, whereas the addition of 0.1 microM vasopressin or 10 mM glycerone, or raising the concentration of glucose from 5 mM to 20 mM had the opposite effect. All these agents caused changes in the concentration of triose phosphates that almost paralleled those of the fructose 1-phosphate concentration. Sorbitol had a similar effect to fructose in causing the formation of fructose 1-phosphate. D-Glyceraldehyde was much less potent in this respect than the ketose and its effect disappeared earlier. The effect of D-glyceraldehyde was reinforced by an increase in the glucose concentration and decreased by glucagon. Both fructose and D-glyceraldehyde stimulated the phosphorylation of glucose as estimated by the release of 3H2O from [2-3H]glucose, but the triose was less potent in this respect than fructose and its effect disappeared earlier. Glucagon and ethanol antagonised the effect of low concentrations of fructose or D-glyceraldehyde on the detritiation of glucose. These results support the proposal that fructose 1-phosphate mediates the effects of fructose, D-glyceraldehyde and sorbitol by relieving the inhibition exerted on glucokinase by a regulatory protein.
从艰难梭菌中部分纯化了1-磷酸果糖激酶，并用于开发1-磷酸果糖和果糖的特异性检测方法。在以葡萄糖作为唯一碳水化合物培养的肝细胞中，1-磷酸果糖的浓度低于检测限（25 pmol/mg蛋白质）。添加果糖（0.05 - 1 mM）导致1-磷酸果糖含量呈浓度依赖性且短暂增加。胰高血糖素（1 microM）和乙醇（10 mM）使与果糖一起培养的细胞中1-磷酸果糖的浓度降低了几倍，而添加0.1 microM血管加压素或10 mM甘油酮，或将葡萄糖浓度从5 mM提高到20 mM则产生相反的效果。所有这些试剂引起的磷酸丙糖浓度变化几乎与1-磷酸果糖浓度的变化平行。山梨醇在导致1-磷酸果糖形成方面与果糖有相似的作用。在这方面，D-甘油醛的作用远不如酮糖，且其作用消失得更早。葡萄糖浓度增加会增强D-甘油醛的作用，而胰高血糖素会使其作用减弱。果糖和D-甘油醛都能刺激葡萄糖的磷酸化，这可通过[2-³H]葡萄糖中³H₂O的释放来估计，但在这方面丙糖的作用不如果糖，且其作用消失得更早。胰高血糖素和乙醇拮抗低浓度果糖或D-甘油醛对葡萄糖脱氚作用的影响。这些结果支持了这样的观点，即1-磷酸果糖通过解除调节蛋白对葡萄糖激酶的抑制来介导果糖、D-甘油醛和山梨醇的作用。
