Enzymes 1,2 and 3 Flashcards
what happens inside the ATP synthase
the middle and lower parts rotate
how does the middle and lower part of ATP synthase rotate
this happens when protons are flowing back into the mitochondria
what does the top part of ATP synthase do
merge ATP and phosphate
what is a cofactor
a non-protein component that is required to help the enzyme to do its job
examples of some cofactors
K+, Mg2+ and Fe2+/Fe3+
what are coenzymes
complex organic molecules, usually produced from a vitamin
examples of coenzymes
FAD, NAD+ and Coenzyme A
what is a prosthetic group
cofactor covalently bound to the enzyme or very tightly associated with the enzyme
what is an apoenzyme
the protein component of an enzyme that contains a cofactor
what is a holoenzyme
“whole enzyme” - the apoenzyme plus the cofactor(s)
what is a substrate
molecule acted on by the enzyme
what is an active site
the very point the reaction takes place
what are the 6 types of class names for enzymes
oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases
what type of reaction does oxidoreductase involve
transfer e-
what type of reaction does transferase involve
group transfers
what type of reaction does hydrolase involve
hydrolysis (transfer chemical groups to water)
what type of reaction does lyases involve
form or add groups to double bonds
what is “useful” energy called
Gibs Free Energy (G)
what type of reaction does ligase involve
formation of C-C, C-S, C-N or C-O bonds
what type of reaction does isomerase involve
transfer groups within molecules (form isomer..)
what is the energy barrier
the energy that is require to get to transition sate from ground state (S)
a spontaneous reaction must have a (delta)G value of…
negative value (-)
what are the 3 ways that enzymes reduce activation energy
entropy, desolvation and induced fit
what types of techniques can you use to understand enzyme function
enzyme kinetics, mutagenesis (the ability to change individual amino acids and see how it affects the properties of the enzyme) and 3D structure
what happens to initial rate of reaction if there is more substrate
there is a higher initial rate of reaction
what can the Vmax tell us
it can tell us how fast a reaction is proceeding when the enzyme is saturated with substrate
if there is two or more substrates, how do they react to the enzyme
random order or ordered with a ternary complex, and no ternary complex formation, order/random sequential mechanism, double displacement
what is a ternary complex
a protein complex containing three different molecules that are bound together
what do allosteric enzymes do
have no reaction speed at the very beginning of the [S]
what does vmax indicate
how fast a reaction is proceeding when the enzyme is saturated with substrate
what does Km depict
the stability of the enzyme-substrate complex (affinity)
what does low and high Km mean
low Km has high substrate affinity and gets to Vmax faster
high Km is the opposite
what is the rate limiting factor of the Michealis-Menten equation
the ES–>EP
what are catalytic antibodies
antibodies that generated specific to a transition state molecule
how does an inhibitor irreversibly bond to an inhibitor
binds to enzyme covalently and thus irreversibly
what does the plateau demonstrates in the Michealis-Menten curve
demonstrates zero order kinetics
what does the plateau on Michealis-Menten curve indicate
the systems or enzyme is saturated with substrate
where is glucokinase found and what is their relation with Km and Vmax
mainly found in the liver and has high Km and Vmax
where is hexokinase found and what is their relation with Km and Vmax
is found everywhere and has low Km and Vmax
what happens when blood glucose goes up after a meal
glucokinase activity increases
describe competitive inhibition binding and how it would appear on a michealis-meten plot
reaches Vmax but increases Km resulting in a right shift compared to normal binding
