Catalysis of the transfer of an arachidonoyl (systematic name, (5Z,8Z,11Z,14Z)-eicosatetraenoyl) group to a sulfur atom on the cysteine of a protein molecule, in the reaction: in the reaction: (5Z,8Z,11Z,14Z)-eicosatetraenoyl-CoA + L-cysteinyl- = CoA + S-(5Z,8Z,11Z,14Z-eicosatetraenoyl)-L-cysteinyl-.
protein-cysteine S-arachidonoyltransferase activity