BAAT
Bile acid-CoA:amino acid N-acyltransferase is an enzyme that in humans is encoded by the BAAT gene.[5]
The protein encoded by this gene is a liver enzyme that catalyzes the transfer of the bile acid moiety from the acyl-CoA thioester to either glycine or taurine, the second step in the formation of bile acid-amino acid conjugates which serve as detergents in the gastrointestinal tract.[5]
Functional assay
[edit]A functional assay was used to determine how well rat bile acid-CoA:amino acid N-acyltransferase (BAAT) performs its normal role of conjugating bile acids with the amino acids glycine and taurine.[6] To do this, the researchers cloned the rat BAAT gene, expressed the enzyme in insect cells, and then tested whether it could produce bile acid conjugates.[6] They found that BAAT activity, protein levels, and gene expression all increased after treatment, suggesting that the enzyme is closely associated with peroxisomes and plays an important role in normal bile acid metabolism.
Immunology
[edit]The BRENDA[7] database explains that BAAT catalyzes the final step of bile acid conjugation by attaching glycine or taurine to bile acids, allowing them to function properly during fat digestion and nutrient absorption.[7] While BAAT is primarily a metabolic enzyme rather than an immune protein, its role is still closely connected to immunology. Proper bile acid metabolism helps maintain a healthy gut environment, supports the intestinal barrier, and promotes the absorption of fat-soluble vitamins such as vitamins A and D, which are essential for normal immune function. In addition, bile acids are now recognized as signaling molecules that influence inflammation and immune cell activity.
NIH findings
[edit]Since BAAT is the enzyme responsible for the final step of bile acid conjugation, it helps determine which bile acids are produced and available to interact with immune cells.[8]The review describes how conjugated bile acids communicate with immune cells through receptors such as FXR and TGR5, helping regulate inflammation, maintain the intestinal barrier, and promote immune homeostasis. It also discusses how bile acids influence the gut microbiome, which in turn shapes both innate and adaptive immune responses.[8]
BAAT connects to immunology because it produces conjugated bile acids, which do much more than help digest fats.[8] These bile acids act as signaling molecules that communicate with immune cells and help regulate inflammation throughout the body. By controlling the production of conjugated bile acids, BAAT indirectly influences immune signaling pathways that maintain a healthy balance between activating and suppressing immune responses.[8] Conjugated bile acids also help preserve the intestinal barrier and support a healthy gut microbiome, both of which are essential for preventing harmful bacteria and toxins from triggering excessive immune reactions.[8]
References
[edit]- 1 2 3 ENSG00000276559 GRCh38: Ensembl release 89: ENSG00000136881, ENSG00000276559 – Ensembl, May 2017
- 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000039653 – Ensembl, May 2017
- ↑ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- ↑ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
- 1 2 "Entrez Gene: BAAT bile acid Coenzyme A: amino acid N-acyltransferase (glycine N-choloyltransferase)".
- 1 2 He, Dongning; Barnes, Stephen; Falany, Charles N. (2003-12-01). "Rat liver bile acid CoA:amino acid N-acyltransferase: expression, characterization, and peroxisomal localization". Journal of Lipid Research. 44 (12): 2242–2249. doi:10.1194/jlr.M300128-JLR200. ISSN 0022-2275. PMID 12951368.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - 1 2 "Information on EC 2.3.1.65 - bile acid-CoA:amino acid N-acyltransferase - BRENDA Enzyme Database". www.brenda-enzymes.org. Retrieved 2026-07-24.
- 1 2 3 4 5 Trammell, Samuel A. J.; Gamon, Luke F.; Gotfryd, Kamil; Michler, Katja Thorøe; Alrehaili, Bandar D.; Rix, Iben; Knop, Filip K.; Gourdon, Pontus; Lee, Yoon-Kwang; Davies, Michael J.; Gillum, Matthew P.; Grevengoed, Trisha J. (September 2023). "Identification of bile acid-CoA:amino acid N-acyltransferase as the hepatic N-acyl taurine synthase for polyunsaturated fatty acids". Journal of Lipid Research. 64 (9) 100361. doi:10.1016/j.jlr.2023.100361. ISSN 1539-7262. PMC 10470208. PMID 36958721.
External links
[edit]- Human BAAT genome location and BAAT gene details page in the UCSC Genome Browser.
Further reading
[edit]- BAAT Functional Ass
- Johnson MR, Barnes S, Kwakye JB, Diasio RB (1991). "Purification and characterization of bile acid-CoA:amino acid N-acyltransferase from human liver". J. Biol. Chem. 266 (16): 10227–33. doi:10.1016/S0021-9258(18)99213-6. PMID 2037576.
- Falany CN, Johnson MR, Barnes S, Diasio RB (1994). "Glycine and taurine conjugation of bile acids by a single enzyme. Molecular cloning and expression of human liver bile acid CoA:amino acid N-acyltransferase". J. Biol. Chem. 269 (30): 19375–9. doi:10.1016/S0021-9258(17)32178-6. PMID 8034703.
- Lench NJ, Telford EA, Andersen SE, et al. (1997). "An EST and STS-based YAC contig map of human chromosome 9q22.3". Genomics. 38 (2): 199–205. doi:10.1006/geno.1996.0616. PMID 8954802.
- Solaas K, Ulvestad A, Söreide O, Kase BF (2000). "Subcellular organization of bile acid amidation in human liver: a key issue in regulating the biosynthesis of bile salts". J. Lipid Res. 41 (7): 1154–62. doi:10.1016/S0022-2275(20)32022-8. PMID 10884298.
- Sfakianos MK, Wilson L, Sakalian M, et al. (2003). "Conserved residues in the putative catalytic triad of human bile acid Coenzyme A:amino acid N-acyltransferase". J. Biol. Chem. 277 (49): 47270–5. doi:10.1074/jbc.M207463200. PMID 12239217.
- Strausberg RL, Feingold EA, Grouse LH, et al. (2003). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. Bibcode:2002PNAS...9916899M. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932.
- Carlton VE, Harris BZ, Puffenberger EG, et al. (2003). "Complex inheritance of familial hypercholanemia with associated mutations in TJP2 and BAAT". Nat. Genet. 34 (1): 91–6. doi:10.1038/ng1147. PMID 12704386. S2CID 21900697.
- Wang H, Tamba M, Kimata M, et al. (2003). "Expression of the activity of cystine/glutamate exchange transporter, system x(c)(-), by xCT and rBAT". Biochem. Biophys. Res. Commun. 305 (3): 611–8. doi:10.1016/S0006-291X(03)00808-8. PMID 12763038.
- O'Byrne J, Hunt MC, Rai DK, et al. (2003). "The human bile acid-CoA:amino acid N-acyltransferase functions in the conjugation of fatty acids to glycine". J. Biol. Chem. 278 (36): 34237–44. doi:10.1074/jbc.M300987200. PMID 12810727.
- Humphray SJ, Oliver K, Hunt AR, et al. (2004). "DNA sequence and analysis of human chromosome 9". Nature. 429 (6990): 369–74. Bibcode:2004Natur.429..369H. doi:10.1038/nature02465. PMC 2734081. PMID 15164053.
- Gerhard DS, Wagner L, Feingold EA, et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMC 528928. PMID 15489334.
- Rual JF, Venkatesan K, Hao T, et al. (2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. Bibcode:2005Natur.437.1173R. doi:10.1038/nature04209. PMID 16189514. S2CID 4427026.
- Pellicoro A, van den Heuvel FA, Geuken M, et al. (2007). "Human and rat bile acid-CoA:amino acid N-acyltransferase are liver-specific peroxisomal enzymes: implications for intracellular bile salt transport". Hepatology. 45 (2): 340–8. doi:10.1002/hep.21528. PMID 17256745. S2CID 6163420.
- Tougou K, Fukuda T, Ito T, et al. (2007). "Genetic polymorphism of bile acid CoA: amino acid N-acyltransferase in Japanese individuals". Drug Metab. Pharmacokinet. 22 (2): 125–8. doi:10.2133/dmpk.22.125. PMID 17495420.
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