Glycolysis
Introduction:
(a). A molecule of alpha-D glucose get converted into 2 molecules of Pyruvic acid.
(b). 2NAD+ gets converted into 2NADH2.
(c). The net gain is 2ATP(total 4ATP) in anaerobic condition by substrate level of phosphorylation.
(d). In aerobic condition the net gain is 8ATP(total 10ATP).
(e). It is a sequential reversible reaction except the step1,step3 and step10 i.e.last step.
(f). This reaction takes place in cytosol of liver cell, kidney e.t.c.
(g). This reaction was discovered by three german biochemist Meyerhof–Parnas ,Gustav Embden,Jakub Karol Parnas.
(h). This is why it is also know as EMP pathway.
There are two phase in Glycolysis
1. Preparatory phase
2. Pay off phase
1. Preparatory phase:
It include first five reaction in which Glucose get converted into 3 Phosphogyceraldehyde (3PGA)
2. Pay off phase:
It include last five reaction in which 3 Phosphoglyceraldehyde (3PGA) get converted into Pyrivic acid.
The 2NAD+ get converted into 2NADH2.
ATP are synthesised in this phase.
The Reaction:
fig. of steps of Glycolysis
REGULATION:
The key enzyme for the regulation of glycolysis are as follows:
1. Hexokinase (step1st)
2. Phosphofructokinase (step3)
3. Pyruvate kinase (step10)
1. Hexokinase enzyme are inhibeted by its own product i.e. Glucose-6-phosphate
when the cellular concentration of Glucose-6-Phosphate is increased by its normal level.
1st step of glycolysis
2. Phosphofructo kinase (PFK) are of two types
PFK1 and PFK2
Phosphofructo kinase enzyme are inhibited by Citrate and ATP, and activated by Cyclic AMP (CAMP).
3rd step of glycolysis(a)
3rd step of glycolysis(b)
3. Pyruvate kinase is the enzyme allosterically inactivated by ATP and activated by Fructo bisphosphatase (FBS).
