Question

In: Chemistry

a) One international unit of an enzyme is defined as the amount that catalyzes: A. The...

a) One international unit of an enzyme is defined as the amount that catalyzes:

A. The formation of one millimole of product in one minute.

B. The formation of one micromole of product in one minute.

C. The formation of one mole of product in one minute.

D. The formation of one micromole of product in one hour.

b) Which of the following expressions is used for determination of K_m?

A. Vo at 1/2 V_max

B. [S] at 1/2 V_max

C. [P] at 1/2 V_max

D. [S] at V_max

c) A protein mixture having MWs of 2, 23, and 40 kilodaltons (kDa) was separated by size exclusion chromatography. Which protein will elute first? Last? Why?

Expert Solution

a) Answer : Option B

The international unit of enzyme activity is Enzyme Unit ( symbol - U or EU). This is defined as the amount that catalyses the formation one micro mol product (or conversion of 1 mol substrate) in one minute.

b) Answer : Option A

This equation comes from Michaels-Menten equation. It is a direct equation.

c) Exclusion chromatography or Gel filtration chromatography is a separation technique base on the size of the components in the mixture. The stationary phase in this chromatographic technique is porous beads of well defined size. During the process of separation the proteins can enter into these pores. The proteins which are small enough to enter into these pores can only stay in stationary phase. The other big sized proteins will be excluded. So in this chromatography big sized proteins will be eluted to first (will come out of the column first) and the smallest ones last.

So in this protein with 40 kDa size will be eluted first and protein with size 4 kDa will be eluted last.

queen_honey_blossom answered 2 years ago

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