GO:0008897:   holo-[acyl-carrier-protein] synthase activity
Catalysis of the reaction: CoA + substrate-serine = adenosine 3",5"-bisphosphate + substrate-serine-4"-phosphopantetheine. The transfer of the 4"-phosphopantetheine (Ppant) co-factor from coenzyme A to the hydroxyl side chain of the serine residue of acyl- or peptidyl-carrier protein (ACP or PCP) to convert them from the apo to the holo form.