1 Glucose à glucose-6-phosphate [glucokinase/hexokinase] , <à fructose-6-phosphate

requires ATP. Reverse reaction done by glucose-6-phosphatase (deficiency of which leads to Von Gierke’s). An impaired ability to make glucose in the liver from either gluconeogenesis or break down glucose from glycogen.

 

 

 

·        a way to generate NADPH (first 3 steps which are oxidative and make 2 NADPH) which is used for anabolic process (lipid and nucleic acid synthesis)  and to reduce oxidative stress (with glutathione)

·        also makes 5 carbon sugars (pentoses) – which are used in making nucleotides and nucleic acids

·        takes place in cytosol

·        an alternative to glycoslysis (which makes NADH)

HMP shunt:

glucose-6-phosphate à 6-phosphogluconolactone, NADPH à6-phosphogluconateà x, NADPHà Ribulose-5-phosphate àààFructose-6-phosphate à fructose-1,6-bisphosphate

·        the first step done by G-6PD (if deficient, get hemolytic anemia because RBCs depend on glycolysis alone to metabolize glucose)

 

 

Fructose-6-phosphate à Fructose-1,6-bisphosphate

(is the rate-limiting step in glycolysis)

·        catalyzed by PFK-1 (phosphfructokinase-1)

 

another possibility for F-6-P:

·        catalyzed by PFK-2 (which is active when dephosphorylated, in liver)

·        F-2,6-BP is the most potent activator of PFK-1