Millington D S, Roe C R, Maltby D A, Inoue F
J Pediatr. 1987 Jan;110(1):56-60. doi: 10.1016/s0022-3476(87)80288-3.
A patient with isovaleryl-coenzyme A dehydrogenase deficiency was given a synthetic oral feed containing L-(2H3-methyl)-leucine of high isotopic purity as the only dietary precursor to the defective enzyme. Metabolites derived from this source were readily distinguished from their unlabeled endogenous counterparts by mass spectrometry. During 6 consecutive days of labeled leucine ingestion, the average daily excretion of labeled metabolites was only about 10% of the total derived from leucine. It is suggested that therapy should be directed toward the control of endogenous protein turnover rather than the restriction of dietary protein intake.
一名异戊酰辅酶A脱氢酶缺乏症患者摄入了一种合成口服饲料，其中含有高同位素纯度的L-(2H3-甲基)-亮氨酸，作为缺陷酶的唯一膳食前体。通过质谱法很容易将来源于此的代谢物与其未标记的内源性对应物区分开来。在连续6天摄入标记亮氨酸期间，标记代谢物的平均每日排泄量仅约为亮氨酸总衍生量的10%。建议治疗应针对控制内源性蛋白质周转，而非限制膳食蛋白质摄入量。
