Fig. 4. Metabolic pathway of ethylene glycol to glyoxylate and other energy compounds.

This consists of PQQ (pyrroloquinoline quinone), which is reduced to PQQH₂ upon conversion of ethylene glycol to glycolaldehyde and other compounds synthesized from glycolate. The enzymes shown are PedE/PedH, PQQ-dependent alcolhol dehydrogenase, Pedl, peroxisomal 3-ketoacyl-COA thiolase, GlcDEF, glycolate dehydrogenase, GlxR, tatronate semialdehyde reductase, Hyi,hydroxypyruvate isomerase and PykA/Pyk, pyruvate kinase.