Fatty acid synthase

Fatty acid synthase (FASN) is a large multifunctional enzyme catalyzing de novo biosynthesis of long-chain saturated fatty acids from acetyl-CoA and malonyl-CoA in the presence of NADPH (UniProt: P49327). The protein contains seven catalytic activities and an acyl carrier protein domain with bound 4'-phosphopantetheine prosthetic group. FASN activity is also required for SARS-CoV-2 replication, indicating broader metabolic relevance in viral infections.

FASN is a key enzyme in lipid metabolism with expression across tissues supporting fatty acid synthesis. No explicit disease associations are documented in UniProt curated data.

FASN was identified in a quantitative proteomics study of post-mortem Alzheimer's disease brain tissue relative to age-matched controls using TMT-labeled, data-dependent acquisition mass spectrometry across four subcellular fractions (Chaparral AD proteomics). The direction of change is ambiguous across fractions, with a mean log2 fold-change of −0.41, suggesting subtle or inconsistent regulation in AD brain that warrants investigation in additional cohorts.