Role of lysine in carnitine biosynthesis in Neurospora crassa

• Published in: The Journal of biological chemistry Vol. 246; no. 13; pp. 4373 - 4375
• Main Authors: Horne, D.W, Tanphaichitr, V, Broquist, H.P
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 10.07.1971
• Subjects: Carbon Isotopes; Carnitine - biosynthesis; Carnitine - isolation & purification; Chromatography, Ion Exchange; Chromatography, Thin Layer; Genetics, Microbial; Lysine - metabolism; Mutation; Neurospora - analysis; Neurospora - metabolism; plant biochemistry; plant physiology
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/s0021-9258(18)62097-6

Neurospora crassa lysine auxotroph strain 33933 was grown on a carnitine-free synthetic medium with either dl -[6- 14 C]lysine (Experiment 1), or dl -[1- 14 C]lysine (Experiment 2) together with 0.2 m m dl -lysine sufficient for ample growth. Carnitine was then purified from mycelial extracts of the mold by ion exchange chromatography and examined for radioactivity. In Experiment 1, radioactivity derived from [6- 14 C]lysine was incorporated into carnitine without dilution; and the radioactivity in such carnitine could not be dissociated from carnitine following thin layer chromatography. In contrast, radioactivity from dl -[1- 14 C]lysine, Experiment 2, was not detected in biosynthesized carnitine. These data thus provide evidence for the direct involvement of a portion of the lysine molecule in carnitine biosynthesis in N. crassa . A rationale for a lysine:carnitine-precursor:product relationship is offered in terms of recently discovered ε- N -methyl lysine derivatives.