Β-Leucine Explained
β-Leucine (beta-leucine) is a beta amino acid and positional isomer of -leucine which is naturally produced in humans via the metabolism of -leucine by the enzyme leucine 2,3-aminomutase. In cobalamin (vitamin B12) deficient individuals, plasma concentrations of β-leucine are elevated.[1]
Biosynthesis and metabolism in humans
A small fraction of metabolism – less than 5% in all tissues except the testes where it accounts for about 33% – is initially catalyzed by leucine aminomutase, producing β-leucine, which is subsequently metabolized into (β-KIC), β-ketoisocaproyl-CoA, and then acetyl-CoA by a series of uncharacterized enzymes.[2] [3]
Notes and References
- Web site: Human Metabolome Database: Showing metabocard for Beta-Leucine (HMDB0003640).
- Book: Kohlmeier M . Nutrient Metabolism: Structures, Functions, and Genes . May 2015 . Academic Press . 978-0-12-387784-0 . 385–388 . 2nd . https://books.google.com/books?id=aTQTAAAAQBAJ&q=beta-hydroxy%20beta-methylbutyrate%20HMB&pg=PA387 . 6 June 2016 . Leucine . Energy fuel: Eventually, most Leu is broken down, providing about 6.0kcal/g. About 60% of ingested Leu is oxidized within a few hours ... Ketogenesis: A significant proportion (40% of an ingested dose) is converted into acetyl-CoA and thereby contributes to the synthesis of ketones, steroids, fatty acids, and other compounds . live . https://web.archive.org/web/20180322000056/https://books.google.com/books?id=aTQTAAAAQBAJ&printsec=frontcover . 22 March 2018 . dmy-all .
Figure 8.57: Metabolism of -leucine
- Web site: Leucine metabolism. BRENDA. Technische Universität Braunschweig. 12 August 2016. live. https://web.archive.org/web/20160817213425/http://www.brenda-enzymes.org/pathways/Maps/pathways/leucine_metabolism.svg. 17 August 2016. dmy-all.
