Schematic of the glycerol metabolic pathway in E. coli.
Protein members of the glycerol metabolic pathway includes
glycerol facilitator (GlpF/AQP), a member of the aquaporin
family of major intrinsic proteins. The soluble glycerol kinase
(GK) phosphorylates glycerol to G3P. Another membrane protein
constituent of this pathway is the transporter for the uptake of
G3P (GlpT) with concomitant exit of Pi. Oxidation of G3P to DHAP
is catalyzed by the monotopic membrane enzyme,
glycerol-3-phosphate dehydrogenase (GlpD), a primary
dehydrogenase. Concurrent with oxidation of G3P is reduction of
flavin adenine dinucleotide (FAD) to FADH, which passes on
electrons to ubiquinone (UQ) forming the reduced form (UQH)
and ultimately shuttling electrons to oxygen or nitrate.