The conversion of a fatty acid to an active fatty acid is catalysed by which of the following enzymes?
Fatty acids must first be converted to an active intermediate before they can be catabolized. This is the only step in the complete degradation of a fatty acid that requires energy from  ATP.  In  the  presence  of  ATP and coenzyme A, the enzyme acyl-CoA synthetase (thiokinase) catalyzes the conversion of a fatty acid (or FFA) to an “active fatty acid” or  acyl-CoA, using one high-energy phosphate and forming AMP and PPi . The PPi is hydrolyzed by inorganic pyrophosphatase with the loss of a further high-energy phosphate, ensuring that the overall reaction goes to completion. Acyl-CoA  synthetases  are  found  in  the  endoplasmic reticulum, peroxisomes, and inside and on the outer membrane of mitochondria.
HARPERS ILLUSTRATED BIOCHEMISTRY30th ed page no. 224
Acyl-CoA  synthetase
Enoyl CoA hydratase
Thiolase
Acyl CoA dehydrogenase