The rules that govern the relationships be- tween enzymatic flux capacities (V_max) and maximum physi- ological flux rates (v) at enzyme-catalyzed steps in pathways are poorly understood. We relate in vitro V_max values with in vivo flux rates for glycogen phosphorylase, hexokinase, and phosphofructokinase, enzymes catalyzing nonequilibrium re- actions, from a variety of muscle types in fishes, insects, birds, and mammals. Flux capacities are in large excess over phys- iological flux rates in low-flux muscles, resulting in low fractional velocities (/100V_max = v/V_max × 100) in vivo.
展开▼
机译：在途径中，对于酶促通量（V_max）和最大生理通量率（v）之间关系的控制规则知之甚少。我们将体外V_max值与糖原磷酸化酶，己糖激酶和磷酸果糖激酶（一种催化非平衡反应的酶）的体内通量速率相关，这些酶来自鱼类，昆虫，鸟类和哺乳动物的多种肌肉类型。低通量肌肉的通量容量远远超过生理通量，导致体内的分数速度较低（/ 100V_max = v / V_max×100）。
展开▼
