+ All Categories
Home > Documents > GLYCOLYSIS

GLYCOLYSIS

Date post: 27-Jan-2016
Category:
Upload: lew
View: 27 times
Download: 0 times
Share this document with a friend
Description:
GLYCOLYSIS. GLUCOSE TRANSPORTERS. METABOLIC FATES OF GLUCOSE. Catabolized to produce ATP Stored as glycogen in liver and muscles Converted to fatty acids and stored as triglycerides in adipose tissue. CARBOHYDRATE CATABOLISM. GLYCOLYSIS. A two-phase pathway in which - PowerPoint PPT Presentation
Popular Tags:
36
GLYCOLYSIS GLYCOLYSIS
Transcript
Page 1: GLYCOLYSIS

GLYCOLYSISGLYCOLYSIS

Page 2: GLYCOLYSIS

TransporterTransporter LocationLocation CharacteristicsCharacteristics

Na+/glucose transporters

Gut Glucose-sodium symport

Na+ independent facilitated diffusion-transporters

GLUT1 All cells, RBCs, brain Low Km

GLUT2 Liver, cells of pancreas, kidney, intestine

High Km

GLUT3 Brain, most cell types Low Km

GLUT4 Muscle, adipose tissue

Insulin-dependent translocation to plasma membrane

GLUT5 Intestine, liver Fructose absorption

GLUCOSE GLUCOSE TRANSPORTERSTRANSPORTERS

Page 3: GLYCOLYSIS

METABOLIC FATES OF METABOLIC FATES OF GLUCOSEGLUCOSE

• Catabolized to produce ATP • Stored as glycogen in liver and

muscles• Converted to fatty acids and stored

as triglycerides in adipose tissue

Page 4: GLYCOLYSIS

CARBOHYDRATE CARBOHYDRATE CATABOLISMCATABOLISM

Page 5: GLYCOLYSIS

GLYCOLYSISGLYCOLYSIS• A two-phase pathway in which

– Glucose is oxidized into pyruvate– NAD+ is reduced to NADH + H+

– ATP is synthesized by substrate-level phosphorylation

Pyruvate– Moves on to the Krebs cycle in an aerobic

environment – Is reduced to lactate in an anaerobic

environment

Page 6: GLYCOLYSIS

GLYCOLYSIS – The GLYCOLYSIS – The phasesphases

Glucose

Fructose 1,6-bisphosphate

2 ATPI. Energy investment phase

2 Pyruvate

4 ATP

2 NADH

II. Energy generation phase

Page 7: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep I.Step I.

GLUCOSE GLUCOSE 6- PHOSPHATE

ATP ADP

HexokinaseGlucokinase

Page 8: GLYCOLYSIS

Hexokinase/GlucokinaseHexokinase/Glucokinase

Hexokinase– Found in most tissues– Broad specificity

– Low Km

– Low Vmax

Makes glucose available to tissues at low blood glucose levels

Page 9: GLYCOLYSIS

Hexokinase/GlucokinaseHexokinase/GlucokinaseGlucokinase

–Found in liver and cells of pancreas–Broad specificity

–High Km

–High Vmax

Clears glucose from blood after meals and at blood glucose

levels > 100 mg/dl

Page 10: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep II.Step II.

GLUCOSE 6- PHOSPHATE

FRUCTOSE 6- PHOSPHATEPhosphoglucose

isomerase

Page 11: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep III.Step III.

FRUCTOSE 6- PHOSPHATE

FRUCTOSE 1, 6- BISPHOSPHATEPhosphofructo

-kinase I

ATP

ADP

Page 12: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISSteps IV, V.Steps IV, V.

FRUCTOSE 1, 6- BISPHOSPHATE

Triose phosphat

e isomerase

Aldolase

GLYCERALDEHYDE 3-PHOSPHATE

DIHYDROXACETONE PHOSPHATE

Page 13: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep VI.Step VI.

GLYCERALDEHYDE 3-PHOSPHATE

1,3- BISPHOSPO-GLYCERATE

PiNAD+ NADH + H+

Glyceraldehyde 3-phosphate

dehydrogenase

Page 14: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep VII.Step VII.

1,3- BISPHOSPHO-GLYCERATE 3- PHOSPHO-GLYCERATEPhosphoglycerate

kinase

ADP ATP

Page 15: GLYCOLYSIS

SUBSTRATE-LEVEL PHOSPHORYLATION

High-energy phosphate groups are transferred directly from phosphorylated substrates to ADP

Page 16: GLYCOLYSIS

1,3- BISPHOSPHO-GLYCERATE

3- PHOSPHO-GLYCERATEPhosphoglycerate

kinase

ADP ATP

2, 3- BISPHOSPHO-GLYCERATE

Mutase Phosphatase

H2O

P-OH

2, 3- BISPHOSPHOGLYCERATE2, 3- BISPHOSPHOGLYCERATE

Page 17: GLYCOLYSIS

Pi

ARSENATE POISONINGARSENATE POISONING

GLYCERALDEHYDE 3-PHOSPHATE

1,3- BISPHOSPOGLYCERATE

3- PHOSPHOGLYCERATE

Glyceraldehyde 3-phosphate

dehydrogenase

PiNAD+

H+ + NADH

ADP

ATP

ARSENATE

GLYCOLYSIS CONTINUES…

ENERGY IS DEPLETED

Page 18: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep VIII.Step VIII.

3- PHOSPHO-GLYCERATE

2- PHOSPHO-GLYCERATE

Phosphoglycerate mutase

Page 19: GLYCOLYSIS

FLOURIDE

GLYCOLYSISGLYCOLYSISStep IX.Step IX.

PHOSPHOENOLPYRUVATEEnolase

H2O

2- PHOSPHO-GLYCERATE

Page 20: GLYCOLYSIS

GLYCOLYSISGLYCOLYSISStep X.Step X.

PHOSPHOENOLPYRUVATE

Pyruvate kinase

ADPATP

PYRUVATE

Page 21: GLYCOLYSIS

GLYCOLYSIS: SUMMARYGLYCOLYSIS: SUMMARY

GLUCOSE + 2NAD+ +2Pi + 2ADP

2 PYRUVATE + 2NADH + 2H+ + 2ATP + 2H2O

Page 22: GLYCOLYSIS

THE FATES OF PYRUVATETHE FATES OF PYRUVATE

• ANAEROBIC CONDITIONSReduced to lactate(In RBCs, the kidney medulla, lens and cornea

of the eye, testes, leukocytes and in muscles during intensive exercise)

• AEROBIC CONDITIONSoxidative decarboxylation to Acetyl CoA (in tissue with high oxidative capacity e.g. cardiac muscle, brain etc. )

Page 23: GLYCOLYSIS

ANAEROBIC CONDITIONSANAEROBIC CONDITIONS

PYRUVATE LACTATE

NADH + H+ NAD+

lactate dehydrogenase

GLYCERALDEHYDE 3-PHOSPHATE

1,3- BISPHOSPHO-GLYCERATE

Page 24: GLYCOLYSIS

ANAEROBIC GLYCOLYSISANAEROBIC GLYCOLYSIS

GLUCOSE + 2Pi + 2ADP

2 Lactate + 2ATP + 2H2O + 2H+

Page 25: GLYCOLYSIS

AEROBIC GLYCOLYSISAEROBIC GLYCOLYSIS

PYRUVATE ACETYL CoAPyruvate

dehydrogenase complex

(E1 + E2 + E3)

CoA-SH NADH + H+

NAD

Page 26: GLYCOLYSIS

For each molecule of glucose entering glycolysis, two molecules of acetyl CoA enter the Krebs cycle

Page 27: GLYCOLYSIS

REGULATION OF REGULATION OF GLYCOLYSISGLYCOLYSIS

•Hexokinase/GlucokinaseHexokinase/Glucokinase•PhosphofructokinasePhosphofructokinase•Pyruvate KinasePyruvate Kinase

Page 28: GLYCOLYSIS

REGULATION OF REGULATION OF HEXOKINASEHEXOKINASE

GLUCOSE

GLUCOSE 6- PHOSPHATE

ATP

ADP

Hexokinase

_

Page 29: GLYCOLYSIS

GLUCOSE

GLUCOSE 6- PHOSPHATE

ATP

ADP

Glucokinase

FRUCTOSE 6- PHOSPHATE

+

_

REGULATION OF REGULATION OF GLUCOKINASEGLUCOKINASE

Page 30: GLYCOLYSIS

Nucleus

GKRP

GLUCOSE

Glucokinase

FRUCTOSE 6- PHOSPHATE

ATP

ADP

GLUCOSE 6- PHOSPHATE GK

Glucokinase

REGULATION OF REGULATION OF GLUCOKINASEGLUCOKINASE

Page 31: GLYCOLYSIS

REGULATION OF PHOSPHOFRUCTOKINASE

1FRUCTOSE 6- PHOSPHATE

FRUCTOSE 1,6- BISPHOSPHATE

Phosphofructokinase 1+ AMP, Fructose AMP, Fructose 2,6 2,6 bisphosphatebisphosphate

_ ATP, ATP, CITRATECITRATE

Page 32: GLYCOLYSIS

REGULATION OF PHOSPHOFRUCTOKINASE

1FRUCTOSE 6- PHOSPHATE

FRUCTOSE 2,6- BISPHOSPHATE

Phosphatase

Well fed state InsulincAMPprotein kinase

Starvation Glucagon cAMP Protein kinase

Phosphofructokinase 2

KinaseP

Page 33: GLYCOLYSIS

REGULATION OF REGULATION OF PYRUVATE KINASEPYRUVATE KINASE

FRUCTOSE 1,6- BISPHOSPHATE

PYRUVATE

Pyruvate kinase

+

Page 34: GLYCOLYSIS

REGULATION OF PYRUVATE KINASEPYRUVATE KINASE

PHOSPHOENOLPYRUVATE

PYRUVATE

Starvation Glucose Glucagon cAMP Protein kinase A

Pyruvate kinase

P

GLUCONEOGENESIS

Page 35: GLYCOLYSIS

GLYCOLYSIS AND OTHER METABOLIC GLYCOLYSIS AND OTHER METABOLIC PATHWAYSPATHWAYSGLUCOSE

GLUCOSE 6 PHOSPHATE

1, 3 BISPHOSPHOGLYCERATE

3 PHOSPHOGLYCERATE

PYRUVATE

ACETYL CoA

5-C sugars

TCA cycle

Glu & other amino acids

Serine

2, 3 BPG

Alanine

Glycerol-P

Fatty acids

TGs

Page 36: GLYCOLYSIS

THANK YOU!


Recommended