Term
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Definition
| process of measuring enzyme catalyzed reaction rate |
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Term
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Definition
| how reaction rate varies as a function of substrate calculation |
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Term
| Why is the use of artificial substrate a more efficient way of measuring the rate of enzyme-mediated activity? |
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Definition
| The artificial substrate is a molecular look-alike so the enzyme can still recognize it but the product is coloured so easy to measure |
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Term
| What is the Beer-Lambert law |
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Definition
A=ecl
where A is absorbance, e is the extinction coefficient, c is concentration and l is the length (usually 1cm) |
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Term
| How is absorbance measured |
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Definition
| spectrophotometry (wavelength 200-700nm) |
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Term
| Absorbance intenstity formula? |
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Definition
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Term
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Definition
| Concentration of substrate over time |
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Term
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Definition
number of moles converted per unit time
= Rate X Volume |
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Term
| What is the SI unit for enzyme activity? |
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Definition
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Term
| What is 1 enzyme unit equal to? |
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Definition
1 umol/min
or 10^-6mol / min |
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Term
| What is specific activity? What is the standard unit? |
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Definition
number of moles converted/min/mg
katals/kg
EA/mass of enzyme |
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Term
| When comparing SA of two different pure enzymes what are we measuring? |
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Definition
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Term
| When comparing SA of pure and impure samples of the same enzyme? |
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Definition
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Term
| What is molar activity? Units? |
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Definition
activity per mole of enzyme
turnover number
SA X molar mass of enzyme |
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Term
When an enzyme is purified, the total amount of protein will _______ while the specific activity will _______
(increase/decrease) |
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Definition
protein decrease
SA increase |
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Term
| What does a zero order graph look like? |
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Definition
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Term
| What does a first order graph look like? |
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Definition
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Term
| What does a second order graph look like? |
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Definition
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Term
| What is the standard formula for a rate law? |
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Definition
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Term
|
Definition
| rate when 100% of the enzyme is occupied |
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Term
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Definition
| Km is the concentration of S at which the rate is 1/2 Vmax |
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Term
| If the [S] = Km what is the rate? |
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Definition
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Term
| A low Km indicates that the enzyme has _____ recognition of the substrate |
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Definition
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Term
| A high Km indicates that the enzyme has _____ recognition of the substrate |
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Definition
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Term
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Definition
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Term
| What is a Michaelis Menton plot? |
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Definition
| Vo vs substrate concetration |
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Term
| What is a Lineweaver Burk plot? |
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Definition
reciprocals of both sides of the Michaelis-Menten plot
1/Vo vs 1/[S] |
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Term
| What is the x-intercept of a lineweaver burk? |
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Definition
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Term
| What is the y-intercept of a lineweaver burk? |
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Definition
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Term
| What is the difference between inactivation and inhibition? |
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Definition
inactivation is usually irreversible
inhibition can usually be reversed by removal of the inhibitor |
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Term
| What kind of chemical reaction causes inactivtation? |
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Definition
| covalent chemical reactions |
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Term
| What kind of chemical reaction results in inhibition? |
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Definition
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Term
| What does competitive inhibition affect? |
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Definition
| affects the ability of the substrate to bind to the enzyme because the inhibitors also bind to the active site |
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Term
| What does non competitive inhibition affect? |
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Definition
| affects the conformation of the enzyme which indirectly prevents the substrate from binding |
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Term
| In competitive inhibition where will the lines intercept? |
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Definition
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Term
| In non competitive inhibition where will the lines intercept? |
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Definition
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Term
| With non competitive inhibition what will be the effect on the Vmax and Km? |
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Definition
Vmax is decreases
Km is constant |
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Term
| With competitive inhibition what will be the effect on Vmax and Km? |
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Definition
Vmax is constant
Km increases |
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Term
| What does competitive inhibition affect? |
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Definition
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Term
| What does non-competitive inhibition affect? |
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Definition
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Term
| What is the formula for a change in Vmax |
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Definition
| Vmax' = Vmax / (1+ [I]/Ki) |
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Term
| What is the formula for a change in Kmax |
|
Definition
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