Figure 2.
Bifidobacterium longum subsp. infantis metabolic pathway for utilization of 2′FL, 3FL, DFL and their constituent monosaccharides. FLs are internalized by ABC transporters and hydrolyzed intracellularly by a set of β-galactosidases and α-fucosidases of various substrate specificities (listed in Fig. 7). The resultant monosaccharides enter the Bifid shunt and fermentative pathways characteristic of this taxon. L-fucose catabolism in bifidobacteria has not yet been fully elucidated and is depicted as predicted in19,23 with modifications. Known or predicted genes implicated in L-fucose catabolism are shown as Blon IDs. The central role of the pyruvate node for metabolism of small fucosylated HMOs is highlighted. Dissipation of the excess of L-fucose via yet unidentified efflux transporters for fucose and pyruvate is shown on the left. Enzymes are in gold, compounds in black, secreted fermentation end products are in green or red (for pyruvate). See Supplemental Table 2 for explanation of abbreviations.
