TY - JOUR
T1 - Inhibition of rat liver acetyl-CoA carboxylase by β,β′-tetramethyl-substituted hexadecanedioic acid (MEDICA 16)
AU - Rose-Kahn, Gene
AU - Bar-Tana, Jacob
PY - 1990/2/6
Y1 - 1990/2/6
N2 - Rat liver acetyl-CoA carboxylase activity was inhibited by the free as well as the CoA monothioester of β,β'-methylsubstituted hexadecanedioic acid (MEDICA 16) (Bar-Tana, J., Rose-Kahn, G. and Srebnik, M. (1985) J. Biol. Chem. 260, 8404-8410 (1985). (1) The CoA monothioester of MEDICA 16 served as a dead-end inhibitor with an apparent Ki of 2 μM and 58 μM for the biotin-carboxylated and noncarboxylated enzyme forms, respectively. MEDICA 16-CoA binding was not mutually exclusive with that of citrate and did not affect the avidin-resistance of rat liver acetyl-CoA carboxylase. (2) The free dioic acid of MEDICA 16 was competitive to citrate, having an apparent Ki of about 70 μM, as compared to a Ka of 2-8 mM for the citrate activator. Inhibition of the carboxylase by the free dioic acid of MEDICA 16 was accompanied by an increase in its avidin resistance. The resultant inhibition of acetyl-CoA carboxylase by MEDICA 16 and its CoA thioester, together with the previously reported citrate-competitive inhibition of ATP-citrate lyase by MEDICA 16, may account for the observed hypolipidemic effect of MEDICA 16 under dietary conditions where liver lipogenesis constitutes a major flux of liver lipid synthesis.
AB - Rat liver acetyl-CoA carboxylase activity was inhibited by the free as well as the CoA monothioester of β,β'-methylsubstituted hexadecanedioic acid (MEDICA 16) (Bar-Tana, J., Rose-Kahn, G. and Srebnik, M. (1985) J. Biol. Chem. 260, 8404-8410 (1985). (1) The CoA monothioester of MEDICA 16 served as a dead-end inhibitor with an apparent Ki of 2 μM and 58 μM for the biotin-carboxylated and noncarboxylated enzyme forms, respectively. MEDICA 16-CoA binding was not mutually exclusive with that of citrate and did not affect the avidin-resistance of rat liver acetyl-CoA carboxylase. (2) The free dioic acid of MEDICA 16 was competitive to citrate, having an apparent Ki of about 70 μM, as compared to a Ka of 2-8 mM for the citrate activator. Inhibition of the carboxylase by the free dioic acid of MEDICA 16 was accompanied by an increase in its avidin resistance. The resultant inhibition of acetyl-CoA carboxylase by MEDICA 16 and its CoA thioester, together with the previously reported citrate-competitive inhibition of ATP-citrate lyase by MEDICA 16, may account for the observed hypolipidemic effect of MEDICA 16 under dietary conditions where liver lipogenesis constitutes a major flux of liver lipid synthesis.
KW - (Rat liver)
KW - Acetyl-CoA carboxylase
KW - Hexadecanedioic acid
KW - Lipogenesis
UR - http://www.scopus.com/inward/record.url?scp=0025141846&partnerID=8YFLogxK
U2 - 10.1016/0005-2760(90)90018-S
DO - 10.1016/0005-2760(90)90018-S
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C2 - 1967952
AN - SCOPUS:0025141846
SN - 0005-2760
VL - 1042
SP - 259
EP - 264
JO - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
JF - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
IS - 2
ER -