Enzymes + Protein Function + Protein Analysis Flashcards
what’s the difference between cofactors and coenzymes?
cofactors are inorganic molecules or metal ions
coenzyme are organic molecules.
how can one increase Vmax?
increase amount of enzyme
what’s the michaelis-menten equation?
v = (Vmax[S])/(Km + [S])
What does Hill’s Coefficient measure?
it quantifies an enzyme’s cooperativity
When Hill’s coefficient is greater than 1, what is indicated?
> 1: positively cooperative binding
after one substrate binds, it’s easier for other substrates to bind (enzyme affinity for other substrates increases)
when hill’s coefficient is less than 1, what is indicated?
<1: negatively cooperative binding
after one substrate binds, it’s harder for other substrates to bind (enzyme affinity for other substrates decreases)
when hill’s coefficient is 1, what is indicated?
the enzyme does not have cooperative binding
what is the shape of the michaelis-menten plot when an enzyme exhibits cooperative binding?
sigmoidal curve (S curve)
What’s the relationship between enzyme activity and temperature?
enzyme activity doubles for a 10 degree increases in temperature until optimum temperature
after optimum temperature, enzyme activity quickly drops off due to denaturation
what is the optimal pH of pepsin, an enzyme that functions in the stomach?
pH 2
what is the optimal pH for pancreatic enzymes that function in the small intestine?
pH 8.5
what’s the effect of competitive inhibition on Km and Vmax?
increases Km
no effect on Vmax
what’s the effect of noncompetitive inhibition on Km and Vmax? what’s the affinity of a noncompetitive inhibitor to enzyme and enzyme-substrate complex?
noncompetitive inhibitors bind equally well to enzyme and enzyme-substrate complex
no effect on Km
decreases Vmax
what’s the effect of uncompetitive inhibition on Km and Vmax? what do uncompetitive inhibitors bind?
uncompetitive inhibitors only bind enzyme-substrate complex
decrease Km
decrease Vmax
what’s the effect of mixed inhibitors on Km and Vmax?
decrease Vmax
increase Km if preferentially bind enzyme over enzyme-substrate complex
decrease Km if preferentially bind enzyme-substrate complex over enzyme
what is the structure and function of collagen?
trihelical structure
makes up ECM in connective tissue
what is the function of elastin?
restoring shape of tissue
part of ECM and it stretches and recoils like a string
what is the function of keratin and what type of filament is it?
keratin is an intermediate filament
provides mechanical integrity to cells (nails, hair)
what is the function of actin?
microfilaments involves in muscle contraction and cytokinesis (cleavage furrow)
what is the function of tubulin?
chromosome separation and intracellular transport
where is the negative and positive end of tubulin located in a cell?
negative end is close to nucleus and positive end is near cell membrane
in what direction does kinesin travel on microtubules?
travels from negative end towards positive end
in what direction does dynein travel on microtubules?
travels from positive end to negative end
does kinesin or dynein bring vesicles of neurotransmitters to the synaptic terminal?
kinesin - travels from negative end of microtubule to positive end of microtubule (tubulin has negative end close to nucleus, soma, and positive end close to synaptic terminal)
