Freyssenet D, Berthon P, Geyssant A, Denis C
Laboratoire de Physiologie GIP-Exercice, Faculté de Médecine, CHU de St-Etienne, Hôpital de St-Jean-Bonnefonds-Pavillon 12, France.
Biochim Biophys Acta. 1994 Jul 29;1186(3):232-6. doi: 10.1016/0005-2728(94)90182-1.
A creatine analogue, beta-guanidinopropionic acid (beta-GPA), was administered in the food (1% w/w) of 8 male rats while 8 control rats received a standard diet. Mitochondrial oxidative capacity and kinetic parameters of mitochondrial ATP synthesis, apparent maximal ATP synthesis rate (Vmax) and apparent Michaelis constant for free ADP (Km), were investigated in the extensor digitorum longus (EDL) muscle. Mitochondrial ATP synthesis rate was measured by a bioluminescent method over a large range of ADP concentration (2-30 microM). As a result of the diet, Vmax was significantly increased (P < 0.05) while Km remained unchanged at around 20 microM. Citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase activities were significantly increased (both P < 0.05). Vmax was tightly correlated with CS activity (P < 0.001; r = 0.84). It was concluded that the increase in maximal mitochondrial ATP synthesis rate after beta-GPA feeding in EDL muscle was essentially due to a general increase in mitochondrial enzyme concentrations.
一种肌酸类似物，β-胍基丙酸（β-GPA），添加到8只雄性大鼠的食物中（1% w/w），而另外8只对照大鼠接受标准饮食。在趾长伸肌（EDL）中研究了线粒体氧化能力以及线粒体ATP合成的动力学参数，即表观最大ATP合成速率（Vmax）和游离ADP的表观米氏常数（Km）。通过生物发光法在较大的ADP浓度范围（2 - 30 μM）内测量线粒体ATP合成速率。饮食干预的结果显示，Vmax显著增加（P < 0.05），而Km在20 μM左右保持不变。柠檬酸合酶（CS）和3-羟基酰基辅酶A脱氢酶活性显著增加（均为P < 0.05）。Vmax与CS活性紧密相关（P < 0.001；r = 0.84）。研究得出结论，在EDL肌肉中喂食β-GPA后线粒体最大ATP合成速率的增加主要是由于线粒体酶浓度的普遍增加。
