EXAM 3 Lec 10 Flashcards
enzymes
flexible and undergo staged shape changes during a catalytic reaction
what do the sequences of amino acids in proteins determine
the shape and potential noncovalent reactions
regulator molecules
change enzyme shape, affecting the activity of enzymes
primary structure
sequence of amino acids linked by peptide bonds
determines how the poly peptide interacts with itself and how it interactions with other proteins, ligands, and macromolecules.
secondary structure
nearby noncovalent interactions
hydrogen bonds in the polypeptide backbone create common folding patterns of alpha helices and beta sheets
tertiary structure
3-dimensional structure of one polypeptide
globular proteins are spherical (enzymes)
fibrous proteins are elongated (structural proteins)
includes secondary structures
quaternary structure
proteins where two or more polypeptides form a functional complex held together by noncovalent bonds
can form the same (CAP protein) or different (neuraminidase) polypeptides
how are proteins shaped and organized
by sequences of amino acids that contribute to shape and potential noncovalent interactions
how can protein shape be controlled
by molecules interacting with the protein
chemical modification of the amino acids
changes in the surrounding environment that affect noncovalent interactions (pH and temperature)
function of enzymes
bind a molecule, convert it to a different one, and then back to the original (bring 2 reactants close and redistribute their electrons)
they change their shape in an orderly process that favors product formation
what does the rate of a reaction include
the time the enzyme spends looking/binding to the substrate (dependent on substrate concentration of the enzyme), as well as the time spent converting it to a product
Vmax
time spent converting the substrate to a product
point of infinite concentration
reaction of the enzyme at low concentrations
the enzyme spends most time looking for the substrate, making the rate low
reaction of the enzyme at high concentrations
the enzyme spends less time looking or the substrate, increasing the rate
Km
one half Vmax
Q10
temperature coefficient
effect of temperature on the rate of the reaction
temperature and activity increase together
continues increasing until the enzyme is heat-denatured
enzyme shape guides substrates (reactants) towards
product formation
how do enzymes affect a reactions energy
they reduce the amount of energy needed to start a reaction
allosteric regulation
an enzyme has two sites for interacting with other compounds
the active site and the allosteric regulatory site
active site
where the substrate binds and is converted into the product
allosteric regulatory site
where another compound binds and affects the activity of the enzyme (usually a compound related to the metabolic pathway of the enzyme)
