Kaufman R A, Broquist H P
J Biol Chem. 1977 Nov 10;252(21):7437-9.
In growing cultures of Neurospora crassa lysine auxotroph 33933, (a) beta-hydroxy-epsilon-N-trimethyllysine and gamma-N-trimethylaminobutyraldehyde, postulated precursors of carnitine in the rat, effectively blocked synthesis of labeles carnitine from epsilon-N-[CH3-3H]trimethyllysine; and (b) beta-hydroxy-epsilon-N[CH3-3H[trimethyllysine and gamma-N-[CH3-3H]trimethylaminobutyraldehyde were effectively utilized for carnitine formation. From these isotopic experiments, the latter steps of carnitine synthesis in Neurospora are postulated to be epsilon-N-trimethyllysine leads to beta-hydroxy-epsilon-N-trimethyllysine leads to gamma-N-trimethylaminobutyraldehyde leads to gamma-butyrobetaine leads to carnitine.
在粗糙脉孢菌赖氨酸营养缺陷型33933的生长培养物中，（a）β-羟基-ε-N-三甲基赖氨酸和γ-N-三甲基氨基丁醛（推测为大鼠中肉碱的前体）有效地阻断了由ε-N-[CH₃-³H]三甲基赖氨酸合成标记肉碱的过程；并且（b）β-羟基-ε-N-[CH₃-³H]三甲基赖氨酸和γ-N-[CH₃-³H]三甲基氨基丁醛被有效地用于肉碱的形成。从这些同位素实验推测，粗糙脉孢菌中肉碱合成的后续步骤为ε-N-三甲基赖氨酸→β-羟基-ε-N-三甲基赖氨酸→γ-N-三甲基氨基丁醛→γ-丁酸甜菜碱→肉碱。
