6057586
Descrição
Mapa Mental por Emma Allde, atualizado more than 1 year ago
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Criado por Emma Allde
quase 8 anos atrás
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Th1L07 Regulation of enzyme
activity
- Allosteric regulation
- regulation of a protein by binding an effector molecule at a
site other than the protein's active site
- that site is the allosteric site
- allow effectors to bind to the protein,
often resulting in a conformational change
involving protein dynamics
- that site is the allosteric site
- Sigmoid curve (compared to hyperbolic
curve of M-M kinetics)
- Allosteric activator
- Opens up active site, making it more open
to substrate
- more or less effective active site
- more or less effective active site
- Negative allosteric effectors
- Eg. ATP and citrate on
phosphofructokinase (metabolism)
- ATP can act as positive regulator
during glycolysis if there is not enough
ATP and citrate
- ATP can act as positive regulator
during glycolysis if there is not enough
ATP and citrate
- Eg. ATP and citrate on
phosphofructokinase (metabolism)
- Positive allosteric effectors
- Eg. - "phosphoenolpyruvate (PEP) and
fructose 1,6 bis phosphate on pyruvate
kinase
- PFK acts as a positive allosteric regulator
of phosphenyolpyruvate to pyruvate (a
later step in glycolysis); good example of
co-ordinated regulation
- PFK acts as a positive allosteric regulator
of phosphenyolpyruvate to pyruvate (a
later step in glycolysis); good example of
co-ordinated regulation
- Eg. - "phosphoenolpyruvate (PEP) and
fructose 1,6 bis phosphate on pyruvate
kinase
- Opens up active site, making it more open
to substrate
- regulation of a protein by binding an effector molecule at a
site other than the protein's active site
- Pharmacological altering of enzyme activity
- Covalent modification by other enzymes
- Most common form is the addition or removal of
phosphate from Ser, Thr, Tyr, His residues
- Dephosphorylation of serine 14
- by phosphorylase phosphatase
- by phosphorylase phosphatase
- Glycogen synthase kinase 3
- phosphorylates at several serine
resides; inactivates the enzyme
entirely
- phosphorylates at several serine
resides; inactivates the enzyme
entirely
- Dephosphorylation of serine 14
- Glucose metabolism
- Coordinated regulation of synthesis and breakdown of
glycogen via adrenaline and glucagon
- Shows how protein phosphorylation may be increasing or
decreasing activity of even catalysis of a different reaction
- Coordinated regulation of synthesis and breakdown of
glycogen via adrenaline and glucagon
- Phosphorylation
(regulation of glucose
metabolism)
- Single cascade system
- Increases activity of glycogen
phosphorylase, which is responsible for
degrading glycogen
- occurs by phosphorylase kinase serine 14 and requires ATP; ALSO reduces
activity of glycogen synthase (synthesises glycogen)
- Single cascade system
- Other
- Adenylylation or AMPylation (Tyr residues, ATP to PPi)
- Uridylylation (Tyr residues, UTP to PPi)"
- Adenylylation or AMPylation (Tyr residues, ATP to PPi)
- Most common form is the addition or removal of
phosphate from Ser, Thr, Tyr, His residues
- Induction or repression of enzyme synthesis
- e.g. High blood glucose levels lead to an increase in insulin production
- Insulin increases rate of synthesis of key enzymes involved
in glucose metabolism
- Glucokinase, phosphofructokinase, pyruvate kinase
- Glucokinase, phosphofructokinase, pyruvate kinase
- Insulin increases rate of synthesis of key enzymes involved
in glucose metabolism
- e.g. High blood glucose levels lead to an increase in insulin production
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