β-Hydroxy β-methylbutyryl-CoA

β-Hydroxy β-methylbutyryl-coenzyme A (HMB-CoA), also known as 3-hydroxyisovaleryl-CoA, is a metabolite of L-leucine that is produced in the human body.[1][2] Its immediate precursors are β-hydroxy β-methylbutyric acid (HMB) and β-methylcrotonoyl-CoA (MC-CoA). It can be metabolized into HMB, MC-CoA, and HMG-CoA in humans.

β-Hydroxy β-methylbutyryl-CoA
Names
IUPAC name
3′-O-Phosphonoadenosine 5′-[(3R)-3-hydroxy-4-{[3-({2-[(3-hydroxy-3-methylbutanoyl)sulfanyl]ethyl}amino)-3-oxopropyl]amino}-2,2-dimethyl-4-oxobutyl dihydrogen diphosphate]
Systematic IUPAC name
O1-{[(2R,3S,4R,5R)-5-(6-Amino-9H-purin-9-yl)-4-hydroxy-3-(phosphonooxy)oxolan-2-yl]methyl} O3-[(3R)-3-hydroxy-4-{[3-({2-[(3-hydroxy-3-methylbutanoyl)sulfanyl]ethyl}amino)-3-oxopropyl]amino}-2,2-dimethyl-4-oxobutyl] dihydrogen diphosphate
Other names
β-hydroxyisovaleryl-CoA
3-hydroxyisovaleryl-CoA
3-hydroxy-3-methylbutyryl-CoA
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
KEGG
  • InChI=1S/C26H44N7O18P3S/c1-25(2,20(37)23(38)29-6-5-15(34)28-7-8-55-16(35)9-26(3,4)39)11-48-54(45,46)51-53(43,44)47-10-14-19(50-52(40,41)42)18(36)24(49-14)33-13-32-17-21(27)30-12-31-22(17)33/h12-14,18-20,24,36-37,39H,5-11H2,1-4H3,(H,28,34)(H,29,38)(H,43,44)(H,45,46)(H2,27,30,31)(H2,40,41,42)/t14-,18-,19-,20+,24-/m1/s1
    Key: PEVZKILCBDEOBT-CITAKDKDSA-N
  • CC(C)(CC(=O)SCCNC(=O)CCNC(=O)[C@@H](C(C)(C)COP(=O)(O)OP(=O)(O)OC[C@@H]1[C@H]([C@H]([C@@H](O1)N2C=NC3=C(N=CN=C32)N)O)OP(=O)(O)O)O)O
Properties
C26H44N7O18P3S
Molar mass 867.649946
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Metabolic pathway

edit


Notes

edit
  1. ^ This reaction is catalyzed by an unknown thioesterase enzyme.[3][4]

References

edit
  1. ^ a b c Wilson JM, Fitschen PJ, Campbell B, Wilson GJ, Zanchi N, Taylor L, Wilborn C, Kalman DS, Stout JR, Hoffman JR, Ziegenfuss TN, Lopez HL, Kreider RB, Smith-Ryan AE, Antonio J (February 2013). "International Society of Sports Nutrition Position Stand: beta-hydroxy-beta-methylbutyrate (HMB)". Journal of the International Society of Sports Nutrition. 10 (1): 6. doi:10.1186/1550-2783-10-6. PMC 3568064. PMID 23374455.
  2. ^ a b c Kohlmeier M (May 2015). "Leucine". Nutrient Metabolism: Structures, Functions, and Genes (2nd ed.). Academic Press. pp. 385–388. ISBN 978-0-12-387784-0. Retrieved 6 June 2016. 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
    Figure 8.57: Metabolism of L-leucine
  3. ^ "KEGG Reaction: R10759". Kyoto Encyclopedia of Genes and Genomes. Kanehisa Laboratories. Retrieved 24 June 2016.
  4. ^ Mock DM, Stratton SL, Horvath TD, Bogusiewicz A, Matthews NI, Henrich CL, Dawson AM, Spencer HJ, Owen SN, Boysen G, Moran JH (November 2011). "Urinary excretion of 3-hydroxyisovaleric acid and 3-hydroxyisovaleryl carnitine increases in response to a leucine challenge in marginally biotin-deficient humans". primary source. The Journal of Nutrition. 141 (11): 1925–1930. doi:10.3945/jn.111.146126. PMC 3192457. PMID 21918059. Metabolic impairment diverts methylcrotonyl CoA to 3-hydroxyisovaleryl CoA in a reaction catalyzed by enoyl-CoA hydratase (22, 23). 3-Hydroxyisovaleryl CoA accumulation can inhibit cellular respiration either directly or via effects on the ratios of acyl CoA:free CoA if further metabolism and detoxification of 3-hydroxyisovaleryl CoA does not occur (22). The transfer to carnitine by 4 carnitine acyl-CoA transferases distributed in subcellular compartments likely serves as an important reservoir for acyl moieties (39–41). 3-Hydroxyisovaleryl CoA is likely detoxified by carnitine acetyltransferase producing 3HIA-carnitine, which is transported across the inner mitochondrial membrane (and hence effectively out of the mitochondria) via carnitine-acylcarnitine translocase (39). 3HIA-carnitine is thought to be either directly deacylated by a hydrolase to 3HIA or to undergo a second CoA exchange to again form 3-hydroxyisovaleryl CoA followed by release of 3HIA and free CoA by a thioesterase.