description
Beta-oxidation begins once fatty acids have been imported into the mitochondrial matrix by carnitine acyltransferases. The beta-oxidation spiral of fatty acids metabolism involves the repetitive removal of two carbon units from the fatty acyl chain. There are four steps to this process: oxidation, hydration, a second oxidation, and finally thiolysis. The last step releases the two-carbon acetyl-CoA and a ready primed acyl-CoA that takes another turn down the spiral. In total each turn of the beta-oxidation spiral produces one NADH, one FADH2, and one acetyl-CoA.Further oxidation of acetyl-CoA via the tricarboxylic acid cycle generates additional FADH2 and NADH. All reduced cofactors are used by the mitochondrial electron transport chain to form ATP. The complete oxidation of a fatty acid molecule produces numerous ATP molecules. Palmitate, used as the model here, produces 129 ATPs.Beta-oxidation pathways differ for saturated and unsaturated fatty acids. The beta-oxidation of saturated fatty acids requires four different enzymatic steps. Beta-oxidation produces and consumes intermediates with a trans configuration; unsaturated fatty acids that have bonds in the cis configuration require three separate enzymatic steps to prepare these molecules for the beta-oxidation pathway

external resources
NCBI:1270015
REACTOME:R-HSA-77289
PUBMED:10527676
PUBMED:11826276
PUBMED:7951672
PUBMED:1431593

genes
ACADL , ACADM , ACADS , ACADVL , ECI1 , DECR1 , ECHS1 , HADHA , HADHB , HADH , MUT , NDUFAB1 , PCCA , PCCB , ACSM3 , ACAA2 , MCAT , ACAD10 , ACAD11 , MCEE , ACSM6 , MMAA ,