Skip to main content
. 2004 Apr 30;558(Pt 1):5–30. doi: 10.1113/jphysiol.2003.058701

Figure 5. Illustration of the proposed peroxisomal lactate shuttle.

Figure 5

Based on (McClelland et al. 2003), Salway (1999) and Baumgart et al. (1996). The outline of reactions displays the β-oxidation of very-long-chain fatty acids with acetyl-CoA release to the cytosol. Although not shown, shortened fatty acyl-CoA molecules could be released to the cytosol as well. Key elements of the peroxisomal lactate shuttle are highlighted in red indicating that NADH is reoxidized to NAD+ inside the peroxisome by the conversion of pyruvate to La−; La− then leaves the peroxisome via the monocarboxylate carrier, MCT2. In the cytosol, La− is converted back to pyruvate with concomitant conversion of NAD+ to NADH, thus delivering reducing equivalents from the peroxisome to the cytosol. The resulting pyruvate returns to the peroxisome via the MCT2 to continue the shuttle. This shuttle provides an avenue for NADH reoxidation in the peroxisome, a necessary process for the continuation of peroxisomal β-oxidation of fatty acids. E1: acyl-CoA oxidase; E2: enoyl-CoA hydratase; E3: L-3-hydroxyacyl-CoA dehydrogenase; E4: thiolase; E5: catalase; pLDH: LDH located inside the peroxisome; cLDH: LDH located in the cytosol, outside the peroxisome; Pyr−: pyruvate; La−: lactate.