Catalyzes specifically the NADPH-dependent reduction of coenzyme A disulfide. Is also active with other disulfide substrates containing at least one 4'-phosphopantethienyl moiety such as 4,4'-diphosphopantethine, but is not able to reduce oxidized glutathione, cystine, pantethine, or H(2)O(2). 2 CoA + NADP(+) = CoA-disulfide + H(+) + NADPH Binds 1 FAD per subunit. Optimum pH is 7.0-8.0. Homodimer. Contains 2 FAD binding domains and a single NADPH binding domain. Reduction of disulfides occurs by a thiol-disulfide exchange reaction, but involves only a single catalytic cysteine residue that forms a stable mixed disulfide with CoA during catalysis. Belongs to the class-III pyridine nucleotide-disulfide oxidoreductase family.