A 15N NMR study on D-lysine metabolism in Neurospora crassa.
The metabolic relationship of D-lysine, L-lysine, and L-pipecolic acid has been investigated in Neurospora crassa. Kinetic experiments show that radioactivity from D-lysine is efficiently incorporated into L-pipecolic acid and that this metabolite is converted to L-lysine. The alpha-amino group from D-[alpha-15N]lysine is lost in the course of its conversion to L-pipecolic acid and is trapped by pyruvate and alpha-keto glutarate to give L-[alpha-15N]alanine and L-[alpha-15N]glutamic acid. These amino acids are devoid of any label, however, when D-[epsilon-15N]lysine is applied to the fungus. As determined by mass and 15N NMR spectrometry the label from D-[epsilon-15N]lysine migrate via L-pipecolic acid into the alpha position of L-lysine, i.e. D-[epsilon-15N]lysine is converted to L-[alpha-15N]lysine. L-Pipecolic acid functions as an intermediate in this conversion.
D000596:Amino Acids / Q000096:biosynthesis; D002250:Carbon Radioisotopes; D007700:Kinetics; D008239:Lysine / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000378:metabolism*; D009587:Nitrogen Isotopes
D000596:Amino Acids; D002250:Carbon Radioisotopes; D009587:Nitrogen Isotopes; D008239:Lysine