4.4 explain the effects of competitive and non-competitive inhibitors on enzyme activity
competitive inhibitor - this slow or stop enzyme controlled reaction
this inhibitor has a similar shape to the enzyme substrate so binds to the enzyme briefly so there will be competition for the active site.
this is reversible because increasing substrate concentration reverses effect
example - enzyme succinic dehydrogenase coverts succinate to fumarate
but another compound malonate as a similar shape to succinate and can fit into the active site of the succinic dehydrogenase. So malonate is a inhibitor
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Non-competitive - can be irreversible or reversible
Irreversible - inhibitor permanently bonds to somewhere other than the active site called the allosteric site. This changes of the shape of the enzyme resulting in the substrate not being able to bind to the active site.
Therefore the enzyme function is blocked no matter how much substrate is added
Example - heavy metals such as mercury and lead may bind permanently to enzyme molecules thus altering the shape of the active site
Reversible - inhibitor bonds to some where other than the active site. This does not affect ability of substrate to fit into active site but it make catalysis impossible.
Therefore increase in substrate concentration does not affect rate
Catalysis will be possible once inhibitor no longer bonds with enzyme
