TY - JOUR
T1 - Participation of two members of the very long-chain acyl-CoA synthetase family in bile acid synthesis and recycling
AU - Mihalik, Stephanie J.
AU - Steinberg, Steven J.
AU - Pei, Zhengtong
AU - Park, Joseph
AU - Kim, Do G.
AU - Heinzer, Ann K.
AU - Dacremont, Georges
AU - Wanders, Ronald J.A.
AU - Cuebas, Dean A.
AU - Smith, Kirby D.
AU - Watkins, Paul A.
PY - 2002/7/5
Y1 - 2002/7/5
N2 - Bile acids are synthesized de novo in the liver from cholesterol and conjugated to glycine or taurine via a complex series of reactions involving multiple organelles. Bile acids secreted into the small intestine are efficiently reabsorbed and reutilized. Activation by thioesterification to CoA is required at two points in bile acid metabolism. First, 3α,7α,12α-trihydroxy-5β-cholestanoic acid, the 27-carbon precursor of cholic acid, must be activated to its CoA derivative before side chain cleavage via peroxisomal β-oxidation. Second, reutilization of cholate and other C24 bile acids requires reactivation prior to re-conjugation. We reported previously that homolog 2 of very long-chain acyl-CoA synthetase (VLCS) can activate cholate (Steinberg, S. J., Mihalik, S. J., Kim, D. G., Cuebas, D. A., and Watkins, P. A. (2000) J. Biol. Chem. 275, 15605-15608). We now show that this enzyme also activates chenodeoxycholate, the secondary bile acids deoxycholate and lithocholate, and 3α,7α,12α-trihydroxy-5β-cholestanoic acid. In contrast, VLCS activated 3α,7α,12α-trihydroxy-5β-cholestanoate, but did not utilize any of the C24 bile acids as substrates. We hypothesize that the primary function of homolog 2 is in the reactivation and recycling of C24 bile acids, whereas VLCS participates in the de novo synthesis pathway. Results of in situ hybridization, topographic orientation, and inhibition studies are consistent with the proposed roles of these enzymes in bile acid metabolism.
AB - Bile acids are synthesized de novo in the liver from cholesterol and conjugated to glycine or taurine via a complex series of reactions involving multiple organelles. Bile acids secreted into the small intestine are efficiently reabsorbed and reutilized. Activation by thioesterification to CoA is required at two points in bile acid metabolism. First, 3α,7α,12α-trihydroxy-5β-cholestanoic acid, the 27-carbon precursor of cholic acid, must be activated to its CoA derivative before side chain cleavage via peroxisomal β-oxidation. Second, reutilization of cholate and other C24 bile acids requires reactivation prior to re-conjugation. We reported previously that homolog 2 of very long-chain acyl-CoA synthetase (VLCS) can activate cholate (Steinberg, S. J., Mihalik, S. J., Kim, D. G., Cuebas, D. A., and Watkins, P. A. (2000) J. Biol. Chem. 275, 15605-15608). We now show that this enzyme also activates chenodeoxycholate, the secondary bile acids deoxycholate and lithocholate, and 3α,7α,12α-trihydroxy-5β-cholestanoic acid. In contrast, VLCS activated 3α,7α,12α-trihydroxy-5β-cholestanoate, but did not utilize any of the C24 bile acids as substrates. We hypothesize that the primary function of homolog 2 is in the reactivation and recycling of C24 bile acids, whereas VLCS participates in the de novo synthesis pathway. Results of in situ hybridization, topographic orientation, and inhibition studies are consistent with the proposed roles of these enzymes in bile acid metabolism.
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U2 - 10.1074/jbc.M203295200
DO - 10.1074/jbc.M203295200
M3 - Article
C2 - 11980911
AN - SCOPUS:0037025401
SN - 0021-9258
VL - 277
SP - 24771
EP - 24779
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 27
ER -