The effect of changing enzyme concentration on rate of reaction

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Independent: Conc.

of enzyme

Control:

Temperature

Volume

of enzyme

Volume

of substrate

Concentration

of substrate

pH

Method: protease

(1% trypsin) & casein solution

Make up diff. conc.

enzyme using distilled water.

Set up water bath for temp. keep constant.

Place 1 test tube of 5cm3

casein solution into water bath alongside second tube contain 2cm3

of 0.2% trypsin.

Allow acclimatise 3mins so

that at same temp. then add trypsin to casein, start stop clock.

Time how long it takes for casein

solution to turn transparent. (Mark ‘X’ on the other side of tube, as soon as

seen through solution stop clock).

Repeat a further 2 times then repeat for next concentration.

Method: catalase in yeast & hydrogen peroxide

Use 1st conc. yeast

solution, acclimitise to desired temp. alongside separate tube of

hydrogen peroxide.

Set up gas syringe and set to 0.

Quickly add peroxide to yeast & attach

gas syringe.

Read off volume of gas produced

every 10mins until 3 readings are the same.

Repeat 3 times for each conc. yeast

solution.

Calculations & outcome:

Rate =

1/time

Conc. increases, rate of reaction

increases until plateau point where all enzymes metabolised all substrate

immediately.

Calculations & outcome:

Rate

= initial rate of reaction = gradient at steepest point from graphs of vol.

against time for each conc. Outcome as protease.

Evaluation issues:

Accurately

make up diff. conc.

Maintain constant temp.

Difficult see cross through solution

Identify end point consistently

Evaluation

Evaluation issues:

Attache

syringe slow allow loss gas.

Reaction

going too quickly to read.

Inaccurate

reading gas syringe.

Inaccurate reading syringes in making up

dilutions.

Method