Enzymes Flashcards
what is catalyst
chemical agent that speeds up reaction without being consumed
what is enzyme
a catalytic protein that speeds up reaction by lowering energy barriers, making reaction faster
define substrate
a reactant that an enzyme acts on
define enzyme-substrate complex
the enzyme bounded to its substrate
what is an active site
the region on the enzyme where the substrate binds
what is substrate specificity
enzymes only act on specific substances
what is enzyme specificity
results from complementary fit between the shape of its active site and the substrates shape
what is induced fit
enzymes change shape due to chemical interactions with the substrate
how can the active site lower Ea barrier
- orienting substrates correctly
- straining substrate bonds
- providing a favourable microenvironment
- covalently bonding to the substrate
how can enzyme activity be affected by conditions within the cell
- overall environmental changes such as pH and temp
- chemicals that specifically influence the enzyme
- the relative concentration of enzyme and substrate
what are cofactors
non-protein enzyme helpers that activate inactive enzymes
- inorganic (metal in ionic form)
- organic/coenzymes
define inhibitors
reduce the level of activity of the enzyme
- toxins, poisons, pesticides, etc.
what are competitive inhibitors
bind to the activation site of an enzyme, competing with the substrate
what are noncompetitive inhibitors
bind to another part of an enzyme, causing the enzyme to change shape and making the activation site less effective
what is allosteric regulation
occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site
