Belfiore F
Enzyme. 1980;25(2):132-7. doi: 10.1159/000459233.
Based on the consideration that normal metabolic processes depend upon the activity of key enzymes (and membrane carriers) as modulated by regulatory factors (hormones, diet, endogenous compounds, age, physical activity, environmental agents), metabolic disorders might be classified into two groups: (I) defects in enzyme synthesis, leading to enzyme deficiency (classical inborn errors of metabolism) or to qualitative (structural) enzyme alterations (entailing unresponsiveness to regulation), in the presence of normal regulatory factors; (II) defects in enzyme regulation, which include metabolic syndromes such as diabetes mellitus, obesity and hyperlipoproteinemias (other than type I), and are due to changes in enzyme activities caused by alterations in regulatory factor(s) (secondary to various causes), in the presence of normally responsive enzymes.
基于正常代谢过程依赖于关键酶（和膜载体）的活性这一考虑，而这些酶的活性由调节因子（激素、饮食、内源性化合物、年龄、身体活动、环境因素）调控，代谢紊乱可分为两类：（I）酶合成缺陷，导致酶缺乏（典型的先天性代谢缺陷）或导致酶的定性（结构）改变（导致对调节无反应），此时调节因子正常；（II）酶调节缺陷，包括糖尿病、肥胖症和高脂蛋白血症（I型除外）等代谢综合征，其原因是调节因子改变（继发于各种原因）导致酶活性变化，而酶本身反应正常。
