In beta oxidation of fatty acids carnitine is required for -

Ans. is 'b' i.e., Transport of long chain fatty acid to mitochondrial inner layer o Formation of acyl CoA (activated fatty acid) takes place in the cytosol,o Further degradation occurs in the mitochondrial matrix.o This creates a problem because the inner mitochondral membrane is impermeable to long chain acyl CoA (activated fatty acid).o To ov ercome this problem, participation of a carrier, carnitine is requiredQ,o It is Synthesized from lysineQ and methionine in liver and kidney.o The transport process, referred to as carnitine shuttle, comprises following steps:-The acyl group af acyl CoA is transferred to carnitine, resulting in formation of fatty acylcamitine. The reaction is catalyzed by rate-limiting enzyme of b-oxidation, carnitine acyl transferase-1: CAT-1 (or carnitine palmitoyltransferase-1), which is located on outer side (cytosolic side) of inner mitochondrial membrane or inner side of outer mitochondrial membraneQAcylcamitine is able to penetrate the inner membraneQ and is transported across the inner mitochondrial membrane by an enzyme translocase (camitine-acylcamitine translocase). Entry of acylcamitine is coupled with exit of carnitine.Once inside the mitochondrial matrix, acyl group of acylcamitine is transferred back to CoA by the enzyme carnitine acyl transferase-II: CAT-II (or carnitine palmitoyl transferase-II) located on the inside of the inner mitochondrial membrane. Acyl-CoA is reformed in mitochondrial matrix with liberation of carnitine which is returned to the cvtosalic side by the translocase (camitine-acylcamitine translocase) in exchange for an incoming acylcamitine.