eww look you're all zyme Flashcards
what type of proteins are enzymes
globular
what are catalysts
alter the rate of chemical reactions without undergoing permanent change themselves
do the free energies of the products or reactants in a catalytic reaction have to be lower
products must be lowerrrrrr
what does evry chem reaction require
AE
do enzymes lower AE, what does this mean
yes, work at lower temps, metabolic processes work faster
what is the active site of an enzyme made of?
relatively small number of AAs - it is a small depression within the much larger enzyme molecule
where does a substrate fit into
enzyme-substrate complex
how is the substrate and enzyme bonded together
temporarily between the AAs in the enzyme active site and the groups in the substrate molecule
what does induced fit model suggest
that the active site of an enzyme forms as the substrate interacts and moulds around the substrate molecule
how does the induced fit actually affect the enzyme
like a glove there is a general shape but it is able to put strain on substrate molecule to induce a catalytic reaction and change shape
what is the general affect of temp on enzymes
temp increase KE of molecules and they will collide more frequently with enzymes’ active sites = more collisions = more enzyme-substrate complexes being formed and so the rate of reaction will increase but with a perpetual increase in temp the hydrogen bonds will begin to break and this will alter the shape of the active - at about 60 degrees it is so disrupted that is has denatured
how does pH affect the active site
a change in pH alter the charge of the amino acids in the active site - as a result the substrate can no longer be attached to the active site and the so the enzyme substrate complex can no longer be formed
what about a significant change in pH what would that do to an enzyme
it could cause the tertiary structures bonding to break - the active site would therefore be change and the es complex cannot be formed
will a change in pH denature an enzyme
no probs only will reduce activity
Define competitive inhibition
They have a similar shape to that of a substrate molecule
Non competitive inhibitors, what are they
Do not bond to the active site as they have a different shape to the substrate so do not compete - bind to a site away from the active site known as the allosteric site - this causes the active the active site of the enzyme to change shape so it is no longer complimentary to the to the substrate - the es complex can no longer be formed.
How will enzyme conc affect the rate of a catalytic reaction
Increasing enzyme conc increases the number of active sites available and for the substrate to collide with.
More ES complexes can form as enzyme conc increases
what is a fibrous protein
they form long chains which run parallel to one another. these chains are linked by cross bridges and so form very stable molecules - one example is collagen
what is the structure of collagen
its primary structure is an unbranched polypeptide chain
- the secondary structure is a polypeptide that is very tightly wound
- lots of amino acid and glycine helps with close packing
- in the tertiary the chain is twisted into a second helix.
- quaternary is made up of three such polypeptides chains wound together like a rope
