2 Flashcards
catalyst
substance that helps speed up a chemical reaction and are not used up or changed during a reaction
anabolism
refers to endergonic pathways involved in biosynthesis, converting simpler molecules into complex molecules fueled by the use of cellular energy
catabolism
refers to exergonic pathways that break down complex molecules into simpler ones
enzyme function
serve as catalysts that lower the activation energy of a reaction
enzyme made of
proteins (amino acids)
active site
where substrates bond to the enzyme
induced fit
enzyme changes its structure slightly to find the best fit between the substrate and active site
slight temp increase affect on enzyme
generally increases reaction rate/enzymes catalyzed
affect on enzymes of increasing temp outside normal range
affects chemical bonds within the active site making them less suitable to bind substrates
high temp affect on enzymes
cause enzymes to denature, losing 3D structure and function. breaks bonds that fold the protein
denaturation
implies loss of secondary, tertiary, or quaternary structure and function without loss of primary structure
pH affect on enzymes
extreme pH values can cause enzymes to denature. active site amino acids have their own acidic/basic properties and are sensitive to changes in pH
substrate concentration affect on enzyme activity
activity is increased at higher concentrations or substrate until it reaches a saturation point at which the enzyme can bind no additional substrate
cofactor and coenzyme function
enzymes do not work optimally, or at all, unless bound to coenzymes or cofactors that alter the enzyme’s active site to bind substrates
cofactors
inorganic ions that help stabilize enzymatic conformation and function
coenzymes
organic helper molecules, usually vitamins, that are required for enzymatic action and are reusable
apoenzyme
enzyme lacking necessary cofactor/enzyme that is inactive
holoenzyme
enzyme with necessary cofactor/enzyme and is active
competitive inhibitor
structurally similar enough to substrate that it can compete for the enzyme’s active site by blocking the substrate from binding
competitive inhibitor concentration
in order to be effective, inhibitor concentration needs to be approx. equal to substrate concentration
noncompetitive (allosteric) inhibitor
binds to enzyme at site other than active site and blocks substrate binding by altering enzyme’s active site
allosteric site
any site on the enzyme other than the active site
noncompetitive inhibitor concentration
one noncompetitive inhibitor is needed per enzyme. equal to the amount of enzymes
allosteric activators
bind to allosteric site, cause change to active site that increases substrate affinity