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15 Cards in this Set
- Front
- Back
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Isozymes are ?
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enzymes encoded by different genes and thus different proteins but catalyze the same reaction.
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Isozymes reside in .....and have different
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different tissues
regulatory properties. |
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hexokinase II is in ________, has a _____ affinity for glucose and Similarly Hexokinase I.
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- muscle
- high |
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Hexokinase is inhibited by its product, ......
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glucose 6-P.
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hexokinase IV found in liver is _____ ______ by glucose-6-P and has ___ affinity for Glucose
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- not inhibited
- low |
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hexokinase IV also called
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Glucokinase
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The different hexokinases of liver and muscle reflect the different ....
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roles of tissues in glucose metabolism.
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Muscle breaks down glucose ..... while liver generates glucose (gluconeogenesis) ....
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- for energy
- for blood glucose homeostasis. |
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With excess glucose in the blood, liver will ..... Therefore, hexokinase IV doesn’t need a .......for glucose as normal glucose concentration in blood is 5 mM.
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take in glucose and metabolize it.
high affinity |
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The regulation of glucokinase is more complex.
HXIV resides in ..... |
the nucleus as it is bound to a regulator protein.
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The binding to HXIV is much tighter when ........ is
present. |
fructose 6-P
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HXIV regulation by Sequestration in the nucleus
What will cause the HXIV to dissociate from the regulator protein and allow the enzyme to be active and be present in the cytosol. |
Glucose competes with fructose 6-P
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Regulation of Phosphofructokinase I (PFKI)
What is the committed step to glycolysis and is allosterically regulated. |
PFKI
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Regulation of Phosphofructokinase I (PFKI)
In PFKI, ATP is a ______ but is also __ ______ ______ as it also binds to an inhibitor site. |
_ substrate
_ an allosteric inhibitor |
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Regulation of Phosphofructokinase I (PFKI)
Other effector molecules are ......... & ...... as an inhibitor. These all have physiological significance. |
AMP, fructose 2,6-bisP as activators and citrate,
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