Publications

• Molecular cloning and expression of rat liver bile acid CoA ligase.

  Falany C.N., Xie X., Wheeler J.B., Wang J., Smith M., He D., Barnes S.

  Bile acid CoA ligase (BAL) is responsible for catalyzing the first step in the conjugation of bile acids with amino acids. Sequencing of putative rat liver BAL cDNAs identified a cDNA (rBAL-1) possessing a 51 nucleotide 5'-untranslated region, an open reading frame of 2,070 bases encoding a 690 aa ... >> More

  Bile acid CoA ligase (BAL) is responsible for catalyzing the first step in the conjugation of bile acids with amino acids. Sequencing of putative rat liver BAL cDNAs identified a cDNA (rBAL-1) possessing a 51 nucleotide 5'-untranslated region, an open reading frame of 2,070 bases encoding a 690 aa protein with a molecular mass of 75,960 Da, and a 138 nucleotide 3'-nontranslated region followed by a poly(A) tail. Identity of the cDNA was established by: 1) the rBAL-1 open reading frame encoded peptides obtained by chemical sequencing of the purified rBAL protein; 2) expressed rBAL-1 protein comigrated with purified rBAL during SDS-polyacrylamide gel electrophoresis; and 3) rBAL-1 expressed in insect Sf9 cells had enzymatic properties that were comparable to the enzyme isolated from rat liver. Evidence for a relationship between fatty acid and bile acid metabolism is suggested by specific inhibition of rBAL-1 by cis-unsaturated fatty acids and its high homology to a human very long chain fatty acid CoA ligase. In summary, these results indicate that the cDNA for rat liver BAL has been isolated and expression of the rBAL cDNA in insect Sf9 cells results in a catalytically active enzyme capable of utilizing several different bile acids as substrates. << Less

  J. Lipid Res. 43:2062-2071(2002) [PubMed] [EuropePMC]

  This publication is cited by 2 other entries.

• Rat liver bile acid CoA:amino acid N-acyltransferase: expression, characterization, and peroxisomal localization.

  He D., Barnes S., Falany C.N.

  Bile acid CoA:amino acid N-acyltransferase (BAT) is responsible for the amidation of bile acids with the amino acids taurine and glycine. Rat liver BAT (rBAT) cDNA was isolated from a rat liver lambdaZAP cDNA library and expressed in Sf9 insect cells using a baculoviral vector. rBAT displayed 65% ... >> More

  Bile acid CoA:amino acid N-acyltransferase (BAT) is responsible for the amidation of bile acids with the amino acids taurine and glycine. Rat liver BAT (rBAT) cDNA was isolated from a rat liver lambdaZAP cDNA library and expressed in Sf9 insect cells using a baculoviral vector. rBAT displayed 65% amino acid sequence homology with human BAT (hBAT) and 85% homology with mouse BAT (mBAT). Similar to hBAT, expressed rBAT was capable of forming both taurine and glycine conjugates with cholyl-CoA. mBAT, which is highly homologous to rBAT, forms only taurine conjugated bile acids (Falany, C. N., H. Fortinberry, E. H. Leiter, and S. Barnes. 1997. Cloning and expression of mouse liver bile acid CoA: Amino acid N-acyltransferase. J. Lipid Res. 38: 86-95). Immunoblot analysis of rat tissues detected rBAT only in rat liver cytosol following homogenization and ultracentrifugation. Subcellular localization of rBAT detected activity and immunoreactive protein in both cytosol and isolated peroxisomes. Rat bile acid CoA ligase (rBAL), the enzyme responsible for the formation of bile acid CoA esters, was detected only in rat liver microsomes. Treatment of rats with clofibrate, a known peroxisomal proliferator, significantly induced rBAT activity, message, and immunoreactive protein in rat liver. Peroxisomal membrane protein-70, a marker for peroxisomes, was also induced by clofibrate, whereas rBAL activity and protein amount were not affected. In summary, rBAT is capable of forming both taurine and glycine bile acid conjugates and the enzyme is localized primarily in peroxisomes in rat liver. << Less

  J. Lipid Res. 44:2242-2249(2003) [PubMed] [EuropePMC]

• 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.

  Falany C.N., Johnson M.R., Barnes S., Diasio R.B.

  In order to establish whether a single enzyme in human liver was capable of conjugating bile acids with both glycine and taurine, a cDNA encoding human liver bile acid-CoA:amino acid N-acyltransferase (hBAT) has been isolated and characterized. A specific immunoaffinity-purified rabbit anti-hBAT p ... >> More

  In order to establish whether a single enzyme in human liver was capable of conjugating bile acids with both glycine and taurine, a cDNA encoding human liver bile acid-CoA:amino acid N-acyltransferase (hBAT) has been isolated and characterized. A specific immunoaffinity-purified rabbit anti-hBAT polyclonal antibody was used to screen a lambda Zap XR human liver cDNA library resulting in the isolation of two unique clones. hBAT8 and hBAT9 (1669 and 1491 base pairs in length, respectively) were isolated following screening of 4 x 10(5) clones of the cDNA library. Restriction mapping and sequence analysis demonstrated that the cDNAs were identical except hBAT8 contained an additional 178 bases of 5' sequence; hBAT8 was completely sequenced, characterized, and used for all subsequent studies. hBAT8 consisted of a 184-nucleotide 5'-nontranslated region, an open reading frame of 1,254 bases predicting a protein of 418 amino acids with a molecular mass of 46,296 Da, and a 3'-nontranslated region of 209 nucleotides followed by a poly(A)+ tail. The identity of the cDNA was confirmed by the following findings: 1) the open reading frame began with an ATG codon and was followed by a nucleotide sequence which, when translated, corresponded exactly to the first 17 NH2-terminal amino acids of purified human liver BAT; 2) cytosol of Escherichia coli XL1-Blue cells transfected with hBAT8 subcloned into an expression vector, pKK233-2, demonstrated significant enzymatic activity for the conjugation of both taurine and glycine with cholic acid; 3) bacterial expression of hBAT8 generated a protein that comigrated with hBAT from human liver during SDS-polyacrylamide gel electrophoresis and cross-reacted with a specific polyclonal rabbit anti-hBAT antibody during immunoblot analysis; 4) kinetic characteristics of the expressed enzyme were very similar to those reported for purified liver BAT. These data demonstrate that a single cDNA is present in human liver which codes for a protein capable of catalyzing the conjugation of cholic acid with both glycine and taurine. << Less

  J. Biol. Chem. 269:19375-19379(1994) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• The human bile acid-CoA:amino acid N-acyltransferase functions in the conjugation of fatty acids to glycine.

  O'Byrne J., Hunt M.C., Rai D.K., Saeki M., Alexson S.E.

  Bile acid-CoA:amino acid N-acyltransferase (BACAT) catalyzes the conjugation of bile acids to glycine and taurine for excretion into bile. By use of site-directed mutagenesis and sequence comparisons, we have identified Cys-235, Asp-328, and His-362 as constituting a catalytic triad in human BACAT ... >> More

  Bile acid-CoA:amino acid N-acyltransferase (BACAT) catalyzes the conjugation of bile acids to glycine and taurine for excretion into bile. By use of site-directed mutagenesis and sequence comparisons, we have identified Cys-235, Asp-328, and His-362 as constituting a catalytic triad in human BACAT (hBACAT) and identifying BACAT as a member of the type I acyl-CoA thioesterase gene family. We therefore hypothesized that hBACAT may also hydrolyze fatty acyl-CoAs and/or conjugate fatty acids to glycine. We show here that recombinant hBACAT also can hydrolyze long- and very long-chain saturated acyl-CoAs (mainly C16:0-C26:0) and by mass spectrometry verified that hBACAT also conjugates fatty acids to glycine. Tissue expression studies showed strong expression of BACAT in liver, gallbladder, and the proximal and distal intestine. However, BACAT is also expressed in a variety of tissues unrelated to bile acid formation and transport, suggesting important functions also in the regulation of intracellular levels of very long-chain fatty acids. Green fluorescent protein localization experiments in human skin fibroblasts showed that the hBACAT enzyme is mainly cytosolic. Therefore, the cytosolic BACAT enzyme may play important roles in protection against toxicity by accumulation of unconjugated bile acids and non-esterified very long-chain fatty acids. << Less

  J. Biol. Chem. 278:34237-34244(2003) [PubMed] [EuropePMC]

  This publication is cited by 17 other entries.