Catalyzes the transfer of endogenously produced octanoic acid from octanoyl-acyl-carrier-protein (octanoyl-ACP) onto the lipoyl domains of lipoate-dependent enzymes such as the protein H of the glycine cleavage system (GCSH) (PubMed:28757203). Lipoyl-ACP can also act as a substrate although octanoyl-ACP is likely to be the physiological substrate (By similarity). {ECO:0000250|UniProtKB:Q9D009, ECO:0000269|PubMed:28757203}. This is the function of Ensembl gene identifier ENSG00000175536 (LIPT2, lipoyl(octanoyl) transferase 2).