enzyme (structure & function)
an organic catalyst, usually a globular protein - functions to speed up the rate of chemical reactions by lowering the "energy of activation
enzyme naming/classification
suffix = "-ase"; prefix = resembles name of substrate molecule to which the enzyme is specific (i.e., DNA polymerase = enzyme that makes polymers of DNA)
apoenzyme
the protein part of an enzyme that requires a non-protein "cofactor" to function; inactive without a cofactor
cofactor
a non-protein, organic molecule (coenzyme) or inorganic ion (i.e., iron, magnesium,zinc, copper ions) that assists an enzyme in its reaction
coenzyme
(a type of cofactor) an organic molecule which carries chemicals or electrons necessary for enzymatic reactions (i.e., vitamins such as NAD+ NADP+ FAD, coenzyme A)
holoenzyme
a complete enzyme comprised of an apoenzyme + a cofactor or coenzyme
activation energy
amount of energy needed to trigger a chemical reaction
enzymes INCREASE EFFICIENCY - enzymes lower the amount of energy to trigger this reaction
induced fit model
1. enzyme associates with specific substrate whose shape is complementary to the enzyme's active site shape
2. enzyme and substrate bind to form an "enzyme substrate complex"
3. bonds within substrate are broken, forming two (or more) products (a CATABOLI
factors influencing rate of enzymatic reactions (4)
1. temperature: heat can speed up the rate of reactions unless the temperature change is so extreme that it changes (denatures) the shape of the enzyme's active site
2. pH: with "optimal" pH, enzymatic activity will operate at a maximum, extremes of pH wi
Enzyme Inhibitors (3)
1. Competitive inhibitors: substances that fit into to active site of enzyme, preventing normal substrate from binding; can be permanent or reversible; reversible binding can be overcome by increasing concentration of substrate
2. Noncompetitive (Alloster