Rogers Q R, Morris J G, Freedland R A
Enzyme. 1977;22(5):348-56. doi: 10.1159/000458816.
The activities of three urea cycle enzymes, several nitrogen catabolic, gluconeogenic, and lipogenic enzymes were measured in the liver of adult cats fed: a commercial kibble; a 17.5 or 70% protein purified diet, or starved for 5 days. Except for an increase in tyrosine transaminase (EC 2.6.1.5) after feeding the high protein diet, there were no changes in the activities of the hepatic enzymes as influenced by dietary protein level. Likewise, starvation had a minimal effect on the activities of these enzymes as compared to that found in similar experiments in rats. These results indicate that the cat may have only minimal capabilities for enzyme adaptation as compared to that found in many herbivores and omnivores and may provide an explanation as to why cats have an unusually high protein requirement as compared to many other mammals.
在喂食以下食物的成年猫肝脏中，测量了三种尿素循环酶、几种氮分解代谢、糖异生和脂肪生成酶的活性：商业粗磨干粮；17.5%或70%蛋白质的纯化饮食，或饥饿5天。除了喂食高蛋白饮食后酪氨酸转氨酶（EC 2.6.1.5）活性增加外，肝脏酶的活性不受饮食蛋白质水平的影响。同样，与在大鼠中进行的类似实验相比，饥饿对这些酶的活性影响最小。这些结果表明，与许多草食动物和杂食动物相比，猫的酶适应性能力可能非常有限，这可能解释了为什么与许多其他哺乳动物相比，猫对蛋白质的需求量异常高。
