Coupled lipoate synthesis and lipoylation:

Not shown in the reaction below is the need to regenerate the 4Fe-4S cluster of Lipoyl-[acyl-carrier-protein] synthase:

Octanoyl-[acyl-carrier-protein]
|
| protein
|/
| Octanoate-[acyl-carrier-protein]-protein-N-octanoyltransferase (LipB)
|\
| acyl-carrier-protein
|
Octanoyl-protein
|
| 2 S-adenosyl methionine
|/
| Lipoate synthase (LipA)
|\
| 2 Met + 2 CH3-Ado + Fe
|
Lipoyl-protein


Alternative to first step using free octanoate:

Octanoate
|
| protein + ATP
|/
| Lipoate-protein ligase A (LplA)
|\
| ADP + Pi
|
Octanoyl-protein


Direct lipoylation:

Lipoate
|
| protein + ATP
|/
| Lipoate-protein ligase A (LplA)
|\
| ADP + Pi
|
Lipoyl-protein


Previous description of Lipoate synthase was incorrect, asserting that the synthesis occured on ACP,
instead of on the protein (error is present in UniProt).

Prevous description of LipB suggested that it transferred lipoate from ACP, rather than octanoate
from ACP.