Microbial fermentative preparation of L-[15N2]lysine and its tracer: application to serum amino acid kinetic studies.
The microorganism Brevibacterium flavum 21129 has been used to produce multigram batches of L-[15N2]lysine of high purity and isotopic enrichment by supplementation of the growth medium with (15NH4)2SO4 of 98.0 atom% excess. The doubly 15N-labeled lysine can be detected at dilutions 10 times greater than singly labeled lysine when isotope dilution curves are analyzed by gas chromatography-mass spectrometry. This enhanced sensitivity permits kinetic measurements of plasma free-lysine isotope content over a 300-fold dilution during 6 h following a single oral bolus of 5 mg/kg body wt. This inexpensive preparation method lends itself to the production of highly useful biochemical compounds for kinetic studies of human nutrition.
D000042:Absorption; D001951:Brevibacterium / Q000378:metabolism; D005285:Fermentation; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007201:Indicator Dilution Techniques; D007553:Isotope Labeling; D007700:Kinetics; D008239:Lysine / Q000032:analysis / Q000096:biosynthesis* / Q000378:metabolism; D009587:Nitrogen Isotopes
D009587:Nitrogen Isotopes; D008239:Lysine