Glycolysis (carbohydrate metabolism).ppt

biochemistry glycolysis

1. 1

2. Defined as series of reactions where glucose
is oxidized to pyruvate or lactate depending
on the presence or absence of oxygen.
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GLYCOLYSIS- DEFINITIONGLYCOLYSIS- DEFINITION

3. •It is occurring in all cells providing the energy.
•Cytoplasm
•Some organs are totally dependent on
Glycolysis like brain, red blood cells

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4. •Produces energy in the form of ATP
•Energy can be generated both in the presence and
absence of oxygen
•Pyruvate kinase deficiency leads to hemolytic anemia
•Glycolysis & cancer cells
•2-deoxy D glucose-relation with glycolysis & Covid
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5. GLYCOLYSIS PATHWAY – Energy investment
phase
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HEX0KINASE GLUCOKINASE
Present in all most
all tissues
Only in Liver&
Pancreas
Acts on all
hexoses
Specific for
Glucose
Not induced by
insulin
Induced by Insulin
High affinity for
glucose
Low affinity for
Glucose
Step 1
Transferase
Step 2
Isomerization
Step3
Tranferase
Step4
cleavage
Step 5
Isomerization

6. GLYCOLYSIS PATHWAY-ENERGY PRODUCING PHASE
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Step 6
OXIDATION
Step 7
TRANSFERASE
STEP 8
ISOMERIZATION
STEP 9
DEHYDRATION
Step 10
TRANSFERASE

7. Each NADH formed in the pathway which
on entering Electron transport chain gives
2.5 ATP
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8. ANAEROBIC GLYCOLYSIS
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1.Under anaerobic conditions, pyruvate is converted to
lactate by the enzyme lactate dehydrogenase (LDH), and the
lactate is transported out of the cell into the circulation.
2. It helps in the regeneration of NAD which is needed for
continuous anareobic glycolysis cycle.

9. ENERGETICS OF GYCOLYSIS
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10. •Idoacetate , Mercurial compounds inhibit the
enzyme GLYCERALDEHYDE 3 PO
4 DEHYDROGENASE.
They have high affinity for SH group & binds with
the SH groups present in the active site of the
enzyme.
•Fluoride inhibits the enzyme ENOLASE
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11. •Hexokinase/ glucokinase
•Phosphofructo kinase 1
•Pyruvate kinase
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12. Any enzyme can be regulated by anyone of
the mechanisms
1. Allosteric regulation
2.Covalent modification
3.Induction/ repression
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13. •Hexokinase
It is regulated by allosteric regulation.
glucose -6 po4 and ATP are inhibiting
the enzyme by allosteric mechanism.
•Glucokinase
It is regulated by induction. It is induced by
Insulin
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14. PHOSPHOFRUCTOKINASE 1
Regulated by Allosteric regulation and Induction
a)Allosteric regulation

Allosteric inhibitors ---ATP, citrate
Allosteric stimulators ---AMP,Fructose2,6 -bisphosphate
b) Induced by Insulin

Insulin increases the synthesis of the enzyme

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15. PYRUVATE KINASE IS REGULATED BY all the three
mechanisms
1.Covalent modification by phosphorylation(active) and
dephosphorylation (inactive)
2. Allosteric regulation
stimulator—AMP, fructose 1,6 bisphosphate
Inhibitor ---ATP
3. Induction by insulin

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16. PFK -2 regulation
•Bifunctional enzyme
•PFK-2 - cuses the formation of frutose 2,6
bisphosphate - stimulates glycolysis
•Fructose 2,6 bisphosphatase- hydrolyses frutose 2,6
bisphosphate- inhibits glycolysis
•exists in two forms -phosphorylated and
dephosphorylated
•glucagon - activates phosphorylated form-Fructose
2,6 bisphosphatase is acive -inhibits glycolysis
•insulin -activates dephosphorylated form-PFK -2
Active- stimulates glycolysis

17. Rapoport-Luebering shunt
In RBCs, glycolysis is modified by the Rapoport-Luebering
shunt.
It is a biochemical pathway in mature erythrocytes
involving the formation of 2,3-bisphosphoglycerate and
which regulates oxygen release from hemoglobin and
delivery to tissues. Hence, the name “ 2,3-
bisphosphglycerate (2,3-BPG) shunt.
2,3 BPG acts as an allosteric regulator of hemoglobin that
has the ability to decrease the affinity of O
2
to hemoglobin
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