Biotinyl_lipoyl_domains are present in biotin-dependent carboxylases/decarboxylases, the dihydrolipoyl acyltransferase component (E2) of 2-oxo acid dehydrogenases, and the H-protein of the glycine cleavage system (GCS). These domains transport CO2, acyl, or methylamine, respectively, between components of the complex/protein via a biotinyl or lipoyl group, which is covalently attached to a highly conserved lysine residue.
Jiyao W et al.(2023). "The conserved domain database in 2023.",