Enzymes and regulation Flashcards
What are enzymes?
Biological catalysts
What are cofactors?
•mostly metal ions or coenzymes, are inorganic and organic chemicals that assist enzymes during the catalysis of reactions.
What are coenzymes?
Non-protein organic molecules that are mostly derivatives of vitamins soluble in water by phosphorylation; they bind apoenzyme to proteins to produce an active holoenzyme.
What is the function of kinases?
They add phosphate groups to a molecule
What is the function of a phosphatase?
Removes a phosphate group from a molecule.
What is the function of a isomerase/mutase?
Interconverts a molecule between two isomers
What is the function of a dehydrogenase?
Removes a hydrogen atom
What is the function of a reductase/oxidase?
To perform redox reactions
How is glycerol-3-phosphate acyltransferase named?
- Glycerol→ (3C) backbone
- Phosphate →attached to C3
- acyl group→carbon chain
- Transferease→ Tranferes an acyl group
What can you can (generally) work out from an enzymes name?
Give an example
Its function
For example: Heoxkinase
Hexo= 6 (in this case it is the hexo sugar-glucose)
Kinase= Adds phosphate groups
What are rate controlling steps?
- The small number of steps in a metabolic pathway that are irreversible.
- They tend to have a lower maximum rate than the rest of the pathway and they control flux which is the movement of product through a pathway
- They tend to be more affected by inhibitors and activators (often metabolites in the same or related pathways)
What can enzyme activity be controlled by?
Enzyme activity can also be controlled by covalent modification e.g. phosphorylation
What is Feedback inhibition?
When the product controls its own synthesis via an early “committed” step
What is feedforward activation?
When a metabolite early in the pathway activates an enzyme further down the pathway.
