Transfers the 4'-phosphopantetheine moiety from coenzyme A to a Ser of acyl-carrier-protein (PubMed:9831524, PubMed:16709676, PubMed:25785780, PubMed:28203522). Involved in post-translational modification of various type-I polyketide synthases required for the formation of both mycolic acids and lipid virulence factors (PubMed:16709676). Acts on Pks13, Mas, PpsA, PpsB, PpsC and PpsD (PubMed:16709676, PubMed:28203522). Also acts on AcpM, the meromycolate extension acyl carrier protein (PubMed:25785780). In addition, is involved in the activation of the acyl carrier protein MbtL and the nonribosomal peptides synthases MbtB and MbtE, which are involved in the biosynthesis of the siderophore mycobactin (PubMed:9831524, PubMed:28203522). Required for the replication and survival of Mycobacterium during the acute and chronic phases of infection in mice. apo-[ACP] + CoA = adenosine 3',5'-bisphosphate + H(+) + holo-[ACP] Inhibited by the amidino-urea compound 1-[(2,6-diethylphenyl)-3-N-ethylcarbamimodoyl]urea (compound 8918). It acts by binding to the phosphopantetheine pocket in the active site. Inhibition by compound 8918 kills M.tuberculosis. Identified as a drug target. Belongs to the P-Pant transferase superfamily.