long-chain fatty acid polyunsaturated fatty acid icosatetraenoic acid 20:4 304.240 304.46690 A 20-carbon, polyunsaturated fatty acid having four double bonds at unspecified positions. C20:4 C20H32O2 CHEBI:36033 OC([*])=O PMID:23475189 chebi_ontology eicosatetraenoic acid eicosatetraenoic acids icosatetraenoic acid icosatetraenoic acids olefinic fatty acid