protein function 1 Flashcards
what are enzymes?
they are biological catalysts that speed up chemical reaction.
what are cofactors?
they are basically required for enzymes catalyse, speed up the chemical reaction.
what is lock-key model?
this is when the active site has to be the same shape as the substrate to fit in as in this model the substrate fits in the active site perfectly with having to make any major atomic rearrangements.
what is the induced fit model?
This is when the substrate presents with a conformational change so that the substrate can fit and then the substrate fits well after the reshape.
what is an activation energy?
it is the minimum energy needed to start a chemical reaction.
what are the optimal conditions
temperature
PH
ionic strength
substrate concentration
what are the 4 types of catalysis?
acid-base
covalent
metal ion
approximation
what are cofactors?
molecules that aid enzyme function
what is an acid-base catalysis?
it is a enzyme that acts a a partial proton donor or acceptor
what is an example of acid-base catalyst?
motor protein-ATPase
what is an covalent catalysis?
it is when the active site is temporarily covalently modified
what is the example of a covalent catalysis?
chymotrypsin
what does a metal-ion catalysis do?
stabilise the negative charge
generate a nucleophile- this increases the acidity of the nearby molecule
allows the metal ion to bind to the substrate.
what is an example of a metal-ion catalysis?
carbonic anhydrase
what does approximation catalysis do?
bring two substrates together.
what is an example of a approximation catalysis?
nucleoside-monophosphate (NMP) kinase
what are coenzyme?
small organic cofactors
what are the examples of coenzymes?
prosthetic groups
cosubstrates
what are prosthetic groups?
they are tightly bound coenzymes
what are cosubstartes?
they are loosely associated coenzymes
what happens in the downward shift in ES curve?
decreases Vmax
what happens in the upward shift in ES curve?
increases Vmax
What happens in the right shift in curve?
increases Km - lower binding
what happens in the left shift curve?
decreases Km - higher binding.
what does Vmax depend on?
the concentration of the enzyme.
what does the glucokinase do in relation to michalis mention kinetics?
high Vmax
high Km
responds to large glucose.
what does the hexokinase do in relation to michalis mention kinetics?
lower Vmax
lower Km
not specific too glucose.
what is happens in the rate-limiting step?
it is the slowest step meaning that it takes time to reach to the end of the path and complete its duties
it has the highest activation energy
this pathway is limited by S
what is the committed step?
it is the first irreversible enzymatic reaction that is specific to a product.
what happens in the competitive?
Vmax remains the same
Km increases so more S is needed
slope is steeper
what happens in the uncompetitive?
Vmax is lower
Km is lower
they is no change in the slope.
what happens in the non-competitive?
the Vmax is lower
Km remains the same
the slope is steeper
what does allosteric protein contain?
distinct regulatory sites
multiple functional sites
what are the examples of allosteric regulation?
haemoglobin tetramer
ATcase
what are zymogens and proenzymes
they are enzymes that need activating by another enzyme in order to function.
