enzymes Flashcards
how do enzymes function?
by lowering activation energy of reactions
what are enzymes biochemically?
proteins. except ribozymes.
what do enzymes NOT do?
do not alter equilibrium constants, do not change the free nergy of G for reaction. not used up in reaction.
what do enzymes act on?
L-isomer of an amino acid or D-isomer of a sugar
exerogonic reaction?
reactions with -G and spontaneously occur. MAY generate energy. makes energy like going downhill in a car.
endergonic reactions?
reactions with +G and REQUIRE energy input to occur. example: you always need energy to go uphill
what factors affect enzymes?
temperature! when temp increases, rate of reactions increase but at temps above 102 F proteins denature
acid enzyme pH?
1.5-2.0 like pepsin in stomach
neutral pH enzymes?
7.3-7.4 such as carbonic anhydrase in RBC
basic pH enzymes?
8.0-9.0 such as trypsin in small intestine
Km is what?
estimated physiological concentration of substrate
what does michaelis-menten curve explain to us?
substrate concentration on activity of many but not all enzymes
compeitive enzymes?
most enzymes. reversible, competitor binds at active site, molecule looks like substrate, no effect on vmax, and increases kM
non competitive enzymes?
allosteric enzymes and hemoglobin. reversible, binds at all allosteric sites, molecule does not look like substrate, decreases vmax, and kinetics are explained by Hill equation that determines who has it
irreversible or poison enzymes?
heavy metals such as silver and mercury, nerve gas, carbon monoxide, and cyanide
