lab 2 - enzymes I Flashcards
what do enzymes do
increase the rate of biochem reactions by lowering the activation energy required for the reaction to occur
what is the catalytic effect of the enzyme determined by
shape of active site
what does the rate of enzyme catalysed reaction depend on
concen of enzyme and substrate
enzyme sensitivity to high temp or extreme pH
presence of regulatory compounds that alter activity
what is enzyme kinetics
how fast an enzyme converts substrate to products and investigating the effects of varying the conditions of a reaction
what is a key parameter of enzyme kinetics
enzyme activity (rate or velocity of the reaction catalysed by the enzyme)
how can enzyme activity be measured
spectrophotometer
what do spectrophotometers measure
amount of light absorbed by the solution (absorbance) relative to how much light passes through the solution (transmittance)
absorbance of light by a molecule
what does the absorbance reading on a spectrophotometer tell us
how much light of the selected wavelength a particular pigment molecule absorbs
low value = low amounts of molecule
increase in value = increase in molecule concen
what can you find from the absorbance value when put on a standard curve
the concen of the solution that had the absorbance value
what is a standard curve
displays the relationship between absorbance and concentration for that pigment
what enzyme was used in lab 2
b-galactosidase
present in lactaid and used to treat lactose intolerance
what is lactose
disaccharide found in dairy
consists of glucose and galactose linked together by b-(1,4) glycosidic bond
(can be broken by b-galactosidase)
how do levels of b-galactosidase change through life
high levels at birth
adequate levels through life in europeans
decrease in asians and indigenous
what is the problem with measuring b-galactosidase
neither the natural substrate or products absorb light
what substrate is used
ONPG
- consists of galactose and o-nitrophenol with same link found in lactose
