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Metabolism of saccharidesVladimíra Kvasnicová
Glucose transport into cells: facilitated diffusion(protein transporter GLUT – various types)
ERYTROCYTES NERVOUS TISSUE
- insulin-independent transport
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
HEPATOCYTES
- insulin-independent transport
FATTY TISSUE MUSCLES
- insulin-DEPENDENT transport
insulin increases number of glc transporters
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Secondary-active transport of GLC: symport with Na+
- small intestine, kidneys
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
Glc-6-P !!!
+ NADPH
= hepatocyte
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Choose correct statement(s) about glucose transport:
a) glc is transported in blood bound to its transport protein
b) insulin increases number of GLUT-4transporters in plasma membrane
c) secondary active transport of glc into cells is found in a small intestine and the kidneys
d) phosphorylated glucose is not transported through cellular membrane
Choose correct statement(s) about glucose transport:
a) glc is transported in blood bound to its transport protein
b) insulin increases number of GLUT-4transporters in plasma membrane
c) secondary active transport of glc into cells is found in a small intestine and the kidneys
d) phosphorylated glucose is not transported through cellular membrane
The figure was accepted from Trends in Biochemical Sciences, reference edition, volume 6, str. 209.Elsevier/North-Holland Biomedical Press, 1981.
1st phase
2nd phase
3rd phase
G
L
Y
C
O
L
Y
S
I
S
The figure has been adopted from: J.Koolman, K.H.Röhm / Color Atlas of Biochemistry, 2nd edition, Thieme 2005
glucose entering
glycolysis
The figure is found at http://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)
The enzymes you must know
The figure is found at http://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
2
2
Products of aerobic glycolysis
Products of anaerobic glycolysis
NADHwas consumed in conversion of
pyruvate to lactate
2,3-BPG shunt
IN ERYTROCYTES:
2,3-BPG ↓↓↓↓ affinity of Hb to O2
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
• glukagon (repression, inhibition by phosphorylation)
• ↑ ATP / AMP• acetyl-CoA
• insulin (induction)• fructose-1,6-bisphosphate (feed foreward regulation)
pyruvate kinase
• ↑↑↑↑ ATP / AMP• citrate• acidic pH
• ↓ ATP / AMP• fructose-2,6-bisphosphate(↑ if ↑ insulin / glucagon)• insulin (induction)
6-phosphofructo-1-kinase (PFK-1)
main regulatory enzyme
(key enzyme)
• fructose-6-phosphate• insulin (induction)• fructose-1-phosphate(liver)
glucokinase
• glucose-6-phosphatehexokinase
inhibitionactivationregulatory enzyme
Regulation of glycolysis
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
IRREVERSIBLE REACTION
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The glucokinase has higher value of Kmthan hexokinase∼ glucokinase has lower affinity to glucose
(it needs more glucose to reach the reaction velocity of Vmax/2)
Km Km
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
IRREVERSIBLE REACTION
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
= substrate level phosphorylation
(ATP formation using energy released from cleavage of an energy rich compound = macroergic compound)
IRREVERSIBLE REACTION
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
= substrate level phosphorylation
Pi +
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
Fate of NADH+H+
MALATE-ASPARTATE SHUTTLE
Transport of reducing equivalents to mitochondria
The figure was accepted
from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc.,
New York, 1997. ISBN 0-471-15451-2
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
GLYCEROL PHOSPHATE SHUTTLE
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
= transamination
= carboxylation = oxidative decarboxylation
= reduction
If glucose is degradated in a glycolysis
a) 2 pyruvates are formed from 1 glucose
b) 2 ATP are consumed
c) reducing equivalents are transported to mitochondria by a shuttle mechanism
d) 2,3-bisphosphoglycerate can be formed as a side product
If glucose is degradated in a glycolysis
a) 2 pyruvates are formed from 1 glucose
b) 2 ATP are consumed
c) reducing equivalents are transported to mitochondria by a shuttle mechanism
d) 2,3-bisphosphoglycerate can be formed as a side product
Choose correct statement(s) about regulation of glycolysis:
a) regulatory enzymes catalyze irreversible reactions
b) glycolysis is inhibited by insulin
c) glycolysis is inhibited if ATP/ADP is high
d) glucokinase - a regulatory enzyme – has higher affinity to glc than hexokinase
Choose correct statement(s) about regulation of glycolysis:
a) regulatory enzymes catalyze irreversible reactions
b) glycolysis is inhibited by insulin
c) glycolysis is inhibited if ATP/ADP is high
d) glucokinase - a regulatory enzyme – has higher affinity to glc than hexokinase
The figure was found at http://www.biochem.arizona.edu/classes/bioc462/462b/graphics/GlycolysisGN
GLehn4Fig14-16.jpg (Dec 2007)
Gluconeogenesis
proceeds as a „reversed glycolysis“
with exception of
3 reactions !
The figure has been adopted from J.Koolman, K.H.Röhm / Color Atlas of Biochemistry, 2nd edition, Thieme 2005
glucose entering
glycolysis
pyruvateentering
gluconeogenesis
Gluconeogenesis
= formation of glucose from
non sugarprecursors
The figure was found at http://www2.mcdaniel.edu/Chemistry/CH3321JPGs/Metabolism/Gluconeogenesis.jpg (Dec 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
in MITOCHONDRIA only
Cori cycle
and muscle
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Glucose-alanine cycle
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
= tuk
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
• insulin (repression)• cortisol, glucagon (induction)
glucose-6-phosphatase
• ↑ AMP / ATP• fructose-2,6-bisphosphate (↑ if ↑insulin / glucagon)• insulin (repression)
• cortisol, glucagon (induction)
fructose-1,6-bisphosphatase
• insulin (repression)• cortisol, glucagon (induction)
phosphoenolpyruvatecarboxykinase
• insulin (repression)• acetyl-Co A• cortisol, glucagon (induction)
pyruvate carboxylase
inhibitionactivationregulatory enzyme
Regulation of gluconeogenesis
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
Gluconeogenesis
Gluconeogenesis
a) starts always from pyruvate
b) is catalyzed by the same enzymes as glycolysis
c) participates in a conversion of carbon skeleton of fatty acids (e.g. palmitic acid) to glucose
d) proceeds only in the liver and the kidneys
Gluconeogenesis
a) starts always from pyruvate
b) is catalyzed by the same enzymes as glycolysis
c) participates in a conversion of carbon skeleton of fatty acids (e.g. palmitic acid) to glucose
d) proceeds only in the liver and the kidneys
Choose correct statement(s) about regulation of gluconeogenesis:
a) it is activated by glucagon
b) regulatory enzymes of gluconeogenesis are identical with regulatory enz. of glycolysis
c) gluconeogenesis is activated during starvation
d) pyruvate carboxylase is one of the regulatory enzymes of gluconeogenesis
Choose correct statement(s) about regulation of gluconeogenesis:
a) it is activated by glucagon
b) regulatory enzymes of gluconeogenesis are identical with regulatory enz. of glycolysis
c) gluconeogenesis is activated during starvation
d) pyruvate carboxylase is one of the regulatory enzymes of gluconeogenesis
GLYCOGEN (Glc)n
The figure was found at http://students.ou.edu/R/Ben.A.Rodriguez-1/glycogen.gif (October 2007)
nonreducing end reducing end
OH
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
Metabolism of glycogen
animation
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
glycogen glucose
ATP
ADPPi
• glucagon, adrenaline
(phosphorylation)
• insulin (induction)• glucose-6-phosphate
glykogen synthase(glycogen synthesis)
• ↑ ATP / AMP• glucose-6-phosphate• glucose
• glucagon, adrenaline
(phosphorylation)
• ↓ ATP / AMP• Ca2+ (muscle)
glykogenphosphorylase(glycogen degradation)
inhibitionactivationregulatory enzyme
Regulation of glycogen metabolism
Glycogen
a) is synthesized by glycogen phosphorylase
b) serves as a source of blood glucose during starvation
c) is broken down if insulin/glucagon is high
d) is synthesized from UDP-glucose
Glycogen
a) is synthesized by glycogen phosphorylase
b) serves as a source of blood glucose during starvation
c) is broken down if insulin/glucagon is high
d) is synthesized from UDP-glucose
The figure is found at http://courses.cm.utexas.edu/archive/Spring2002/CH339K/Robertus/overheads-3/ch15_pentose-alternatives.jpg (Dec 2006)
Pentose cycle(= Hexose MonoPhosphate Pathway, HMPP)
IRREVERSIBLE
REVERSIBLE(interconversion of
saccharide monophosphates)
The figure is found at http://web.indstate.edu/thcme/mwking/pentose-phosphate-pathway.html (Dec 2006)
The figure is found at http://web.indstate.edu/thcme/mwking/pentose-phosphate-pathway.html (Dec 2006)
intermediates of glycolysis
synthesis of nucleotides
The figure is found at http://www.richmond.edu/~jbell2/14F34.JPG (Dec 2006)
The figure is found at http://courses.cm.utexas.edu/archive/Spring2002/CH339K/Robertus/overheads-3/ch15_pentose-alternatives.jpg (Dec 2006)
Regulation of HMPP
• on the level of substrates availability and products consumption
↑↑↑↑ NADPH / NADP+
reaction using NADP+ are inhibited by lackof the coenzyme
Pentose cycle
a) is a source of NADH+H+
b) includes reactions which are able to transform glucose to 6 CO2
c) is regulated on the level ofglucose-6-phosphate dehydrogenase
d) is interconnected with glycolysis by glc-6-P, fructose-6-P and glyceraldehyde-3-P
Pentose cycle
a) is a source of NADH+H+
b) includes reactions which are able to transform glucose to 6 CO2
c) is regulated on the level ofglucose-6-phosphate dehydrogenase
d) is interconnected with glycolysis by glc-6-P, fructose-6-P and glyceraldehyde-3-P
Metabolism of fructose in the liver
The figure is found at http://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)
glycolysis or gluconeogenesis
synthesis of TAG
The figure was accepted from Devlin, T. M. (editor): Textbook of Biochemistry with Clinical Correlations, 4th ed. Wiley-Liss, Inc., New York, 1997. ISBN 0-471-15451-2
Fructose
a) can be phosphorylated either to fru-6-Por to fru-1-P
b) can be transformed to body fat
c) in a form of fru-1-P inhibits glucokinase
d) can not be transformed to glucose in the human body
Fructose
a) can be phosphorylated either to fru-6-Por to fru-1-P
b) can be transformed to body fat
c) in a form of fru-1-P inhibits glucokinase
d) can not be transformed to glucose in the human body
Metabolism of galactose
The figure is found at http://web.indstate.edu/thcme/mwking/glycolysis.html (Jan 2007)
epimerizationproceeds on the level of
UDP-derivatives
The figure is found at http://www.kumc.edu/research/medicine/biochemistry/bioc800/car02fra.htm (Jan 2007)
Synthesis of glucuronic acid
Glucose can be transformed to
a) ribose: HMPP participates in the conversion
b) fructose, e.g. glc → glucitol → fructose
c) glucuronic acid: by oxidation of glucose on C1
d) galactose: galactose is 2-epimer of glucose
Glucose can be transformed to
a) ribose: HMPP participates in the conversion
b) fructose, e.g. glc → glucitol → fructose
c) glucuronic acid: by oxidation of glucose on C1
d) galactose: galactose is 2-epimer of glucose
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