Question

The desaturation of fatty acids is a 4 electron process. From where do the 4 electrons originate, and which molecule is the final electron acceptor?

Answer 1

The desaturation of fatty acids is a 4 electron process. From where do the 4 electrons originate, and which molecule is the final electron acceptor?

The 4 electrons required for the desaturation of fatty acids comes from 2 molecules of cytochrome b5 (Fe2+) which gets oxidized into cytochrome b5 (Fe3+) while donating the electrons for the fatty acid desaturation. This oxidized cytochrome b5 is reduced by cytochrome b5 reductase with the help of FADH2. This FADH2 is regenerated by NADPH.

The final electron acceptor of this reaction is oxygen (O2) which becomes water upon accepting electrons.