Subsystem: Glycerol and Glycerol-3-phosphate Uptake and Utilization
This subsystem's description is:
Glycerol-3-phosphate is an important intermediate both in glycolysis and in phospholipid biosynthesis.
Glycerol uptake in bacteria is mediated by the glycerol diffusion facilitator, an integral membrane protein catalyzing the rapid equilibration of concentration gradients of glycerol across the cytoplasmic membrane. Intracellular glycerol is converted to Glycerol-3-Phosphate (G3P) by the enzyme glycerol kinase that uses ATP as phosphoryl donor. Glycerol-3-P is not a substrate of the glycerol diffusion facilitator and thus remains in the cell, where it is further metabolized. As a result, the driving force for the uptake of glycerol is generated by the phosphorylation of glycerol by glycerol kinase.
In addition, many organisms possess two systems the salvage of glycerophosphoryl diesters, the Glp system and the Ugp system.
The Ugp and the GlpT transport systems, both of which can transport G3P against the concentration gradient, are well adapted to the two different physiological situations:
a) phosphate starvation;
b) the availability of glycerol and glycerol-containing compounds as a carbon source.
======== VARIANT CODES: =================
Vaiants 1, 2 or 3 - digit before dot shows how many Glycerol uptake systems the organism possesses one (1), two (2) or three(3).
Digits after dot show what kind of transport is available:
1 for GlpF - Glycerol uptake facilitator protein,
2 for GlpT transport system,
3 for Ugp transport system.
Variant 7 - no uptake systems known, but just utilization of intracellular glycerol and glycerol-3-P(G3P) to glyceron phosphate (GAP) -like in all Shewanellas (except Shewanella putrefaciens CN-32)
Code 3.123 for Escherichia coli K12 - means that all three transport system are available in this organism.
Code 2.12 for Bacillus subtilis - shows that there are two glycerol transport systems: Glycerol uptake facilitator protein and GlpT transport system.
For more information, please check out the description and the additional notes tabs, below
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