BIO-309
BIOCHEMISTRY I
XII. WEEK
•REGULATION OF METABOLIC PATHWAYS
•Enzymes that enable the regulation of glycolytic
and gluconeogenesis pathways,
LECTURE CONTENTS OF LECTURE CONTENTS OF
12th WEEK
12th WEEK
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•Controls of hexokinase IV and hexokinase I,
•Fosfofruktokinaz-1 and
Fructose 1,6-Bisphosphatase
Regulation of pyruvate kinase,
•Allosteric arrangement and
covalent modifications,
•Enzyme catalyzed reactions occurring in a cell should be under control.
•Studies have shown that
metabolic pathway control is performed by several
enzymes.
• Glycolysis and gluconeogenesis use seven common enzymes
that are catalyzed by recycled reactions.
• In three steps, both glycolysis and gluconeogenesis are
controlled by irreversible
reactions.
• The kinetic properties of the
glucokinase (hexokinase IV) found in the liver determine the function of the enzyme.
• When the blood glucose is low, it releases the glucose to the blood.
It also metabolizes the glucose
from the blood when the blood
glucose concentration rises.
• The phosphofructokinase-1 enzyme is regulated
allosterically by ATP and citrate
• Fructose 2,6-biphosphate is the allosteric modulator alos its
activator of
phosphofructokinase-1.
•Pyruvate kinase is
allosterically inhibited by ATP and liver isozyme is inhibited by cyclic AMP-dependent
phosphorylation.
•Gluconeogenesis is regulated by pyruvate carboxylase
(activated by acetyl-CoA)
fructose 1,6 bisphosphatase (inhibited by fructose 2,6
bisphosphate and AMP).
•Both roads are arranged
mutually allosterically.
• METABOLIC REGULATIONS RELATED TO THE CONTROL OF GLYCOLYSIS
AND GLUCONEOGENESIS ON THE
UNION WILL BE DISCUSSED.
REFERENCES
MAIN :
Lehninger Principles of Biochemistry, DavidLehninger Principles of Biochemistry, David L. Nelson, Michael M. Cox, 5th Edition, 2013.L. Nelson, Michael M. Cox, 5th Edition, 2013.
Principles of Biochemistry, H. R. Horton, L. A.
Principles of Biochemistry, H. R. Horton, L. A.
Moran, K. G. Scrimgeour, M. D. Perry, J. D. Rawn, Moran, K. G. Scrimgeour, M. D. Perry, J. D. Rawn,
Pearson Prentis Hall, 2006.
Pearson Prentis Hall, 2006.
Color Atlas of Biochemistry, J. Koolman, K. H.
Color Atlas of Biochemistry, J. Koolman, K. H.
Roehm, Georg Thieme Verlag, 2005.
Roehm, Georg Thieme Verlag, 2005.
Harper’s Illustrated BiochemIstry, R. K. Murray, Harper’s Illustrated BiochemIstry, R. K. Murray, D. K. Granner, P. A. Mayes, V. W. Rodwell, Lange D. K. Granner, P. A. Mayes, V. W. Rodwell, Lange Medical Books/McGraw-Hill Medical PublishIng Medical Books/McGraw-Hill Medical PublishIng
DIvIsIon, 2003.
DIvIsIon, 2003.
Basic Concepts in Biochemistry, A Student’s Basic Concepts in Biochemistry, A Student’s Survival Guide, H. F. Gilbert, McGraw-Hill Health Survival Guide, H. F. Gilbert, McGraw-Hill Health
Proffesions Division, 2000 Proffesions Division, 2000.
