Final answer:
Acyl-CoA dehydrogenase is an enzyme essential for the ß-oxidation of fatty acids, not for fatty acid synthesis. It introduces a double bond into acyl-CoA, with FAD being reduced to FADH2, which contributes to ATP production through the electron transport chain.
Step-by-step explanation:
The enzyme Acyl-CoA dehydrogenase plays a crucial role in the ß-oxidation of fatty acids, which is the metabolic process that breaks down fatty acids to produce energy. This enzyme catalyzes the first step in the ß-oxidation pathway, where a double bond is introduced between the alpha (α) and beta (ß) carbon atoms of the acyl-CoA molecule. In this reaction, the coenzyme Flavin Adenine Dinucleotide (FAD) is reduced to FADH2, capturing the hydrogen atoms removed from the fatty acyl-CoA. This FADH2 subsequently enters the electron transport chain, where it is oxidized to generate ATP.
In contrast, fatty acid synthesis occurs in the cytosol of cells and involves a different set of enzymes. The enzyme fatty acid synthase is responsible for the iterative addition of two-carbon units to elongate the fatty acid chain. This process is reductive and uses energy in the form of ATP and reducing equivalents from NADPH. Therefore, Acyl-CoA dehydrogenase is not involved in fatty acid synthesis but rather in fatty acid degradation.