Metabolic Pathway Regulation Flashcards
What are metabolic pathways regulated by?
Enzymes.
What is the point of metabolic regulation?
Dynamic regulation - maintain energy homeostasis
Defective regulation - metabolism linked to several diseases. ex: diabetes.
What controls transcription?
Both extracellular and intracellular signals.
What is the role of allosteric modulators?
These change the enzyme conformation and thereby turn enzyme activity on/off
- major energy indicators in cells often allosteric modulators.
Ex: ATP, AMP
What is the main enzyme process which is very important in the covalent modification ‘molecular switch’?
Phosphorylation/dephosphorylation
What are the 3 amino acid residues which phosphorylation on enzyme occurs on?
Serine
Threonine
Tyrosine
Phosphorylation on enzyme.
What is a quantity regulation on metabolic enzyme catalytic activity?
Amount of the enzyme
- controlled by enzyme turnover & degradation and the transcription/translation of its mRNA.
What are four of modes of regulating enzyme catalysed metabolic reactions?
- association with regulatory proteins
- Allosteric association
- sequestration - compartmentation.
- covalent modifications
What are the major hormones which control enzymes in metabolism?
- insulin
- glucagon
- adrenaline
What are the 2 main hormones which are involved in the metabolism relevant to blood glucose?
Insulin - released from pancreas in response to high blood (glucose)
Glucagon - released from the pancreas in response to low blood (glucose)
What is the role of adrenaline?
Released from the adrenal medulla. Role : - low blood glucose - anticipation - stress
What do all hormones act on?
They act reversibly on specific receptors = proteins.
These receptors respond to hormones and regulate molecular enzyme catalysed signalling cascades in cells.
What is usually the result of specific receptors - hormones?
Phosphorylation - turning on/off = regulation
Where are the specific receptors for insulin and glucagon?
What type are they?
Lock and key.
These receptors are on many cell types mainly liver and fat cells.
Where are the specific receptors for adrenaline?
These are in many cell types primarily skeletal and fat cells.
