enzymes core prac Flashcards
(18 cards)
blurt
measuring reactants used up and products produced?
milk
lipase
bread
higher amount of enzymes is DIRECTLY proportional to and increase in the INITIAL ROR provided the substrate remains in excess
induced fit model
only a specifically shaped substrate will induce the correct change the shape of an enzymes active site
this slight change in the enzymes active site enables the subtrates to react
Whatre we investigating
the effect of enzyme conc on initial ROR
DV
time taken for enzyme to break down substrate (s)/ initial rate calculated as
CVs + how to control
-temperature (measure temp of water bath with a thermometer and make sure its constant),
-vol of enzyme solution (meaning the solution as a whole, not the conc of protease within the solution, these are changed) 2cm3 of protease solution should be used each time,
-vol of substrate 5cm3 of casein solution should be used each time
-conc of substrate- same conc of casein should be used each time
make sure no acid enters casein solution as casein will hydrolyse in acid
IV
concentration of protease (trypsin)/enzyme conc
what is casein
an enzyme found in milk
what is protease
an enzyme that catalyses hydrolysis of proteins
a digestive enzyme
what does it signify when casein solution turns clear
casein has been hydrolysed into amio acids
casein is white/cloudy and insoluble amino acids are clear and so
what to plot on graph to find initial ROR
x-axis=time
y-axis=vol of products released cm3
results plotted should show a curve with positive correlation that eventually plateaus
how to find initial ROR using a graph
-place ruler equal distances from the curve from both sides from where its touching the curve
-use a ruler to find steepest angle
draw a line tangent to it?
-calculate gradient of the tangent
-y/x
-this gives you the initial ROR
method
-1cm3 protease into 2cm3 casein
colorimeter to calculate % transmission every 10 seconds for 3 mins, repeat 3 times for each enzyme conc
-graph results and calc initial rate
-x-axis= time y-axis=% transmission
risks and hazards
enzymes can be allergens, wear goggles
what is % transmission
amount of light that has passed through the substance in the cuvette and been detected on the other side
higher the % transmission the greater the ROR, more casein has been hydrolysed so more light passed through, less pigmented
how is % transmission measured
using a colorimeter at 5 min intervals, rinsing cuvette with distilled water after every reading
what filter on colorimeter
550 nm
what happens if you increase substrate conc
will increase ROR directly proportionally as long as there are free active sites
if there are no more active sites then enzyme conc is the limiting factor so addition of subtrates wont increase ROR
ROR will plateau
what is trypsin
a type of protease
