Inhibition of carnitine acetyltransferase by mildronate, a regulator of energy metabolism.
Carnitine acetyltransferase (CrAT; EC 2.3.1.7) catalyzes the reversible transfer of acetyl groups between acetyl-coenzyme A (acetyl-CoA) and L-carnitine; it also regulates the cellular pool of CoA and the availability of activated acetyl groups. In this study, biochemical measurements, saturation transfer difference (STD) nuclear magnetic resonance (NMR) spectroscopy, and molecular docking were applied to give insights into the CrAT binding of a synthetic inhibitor, the cardioprotective drug mildronate (3-(2,2,2-trimethylhydrazinium)-propionate). The obtained results show that mildronate inhibits CrAT in a competitive manner through binding to the carnitine binding site, not the acetyl-CoA binding site. The bound conformation of mildronate closely resembles that of carnitine except for the orientation of the trimethylammonium group, which in the mildronate molecule is exposed to the solvent. The dissociation constant of the mildronate CrAT complex is approximately 0.1 mM, and the K(i) is 1.6 mM. The results suggest that the cardioprotective effect of mildronate might be partially mediated by CrAT inhibition and concomitant regulation of cellular energy metabolism pathways.
Jaudzems
Kristaps
K
Latvian Institute of Organic Synthesis, Riga, Latvia.
Kuka
Janis
J
Gutsaits
Aleksandrs
A
Zinovjevs
Kirils
K
Kalvinsh
Ivars
I
Liepinsh
Edgars
E
Liepinsh
Edvards
E
Dambrova
Maija
M
D000818:Animals; D001665:Binding Sites; D055162:Biocatalysis; D002317:Cardiovascular Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002332:Carnitine O-Acetyltransferase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D010856:Columbidae; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008763:Methylhydrazines / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D056004:Molecular Dynamics Simulation; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D002317:Cardiovascular Agents; D004791:Enzyme Inhibitors; D008763:Methylhydrazines; C050147:3-(2,2,2-trimethylhydrazine)propionate; D002332:Carnitine O-Acetyltransferase