FACTORS AFFECTING ENZYME ACTIVITY Flashcards
are water-soluble proteins that function as biological catalysts for the reaction involve in metabolism
enzymes
Enzyme Structure
Two general structures:
Simple enzyme
Conjugated enzyme
an enzyme composed
only of protein (amino acids chains)
Simple enzyme
an enzyme that has
a non-protein (cofactor) part in addition to a
protein part.
Conjugated enzyme
s the relatively small part of an
enzyme’s structure that is actually involved in
catalysis
active site
It is usually a _________________ location in
the enzyme.
‘crevicelike’
In this model, the active site in the enzyme has
a fixed, rigid geometrical conformation. It
explain the action of numerous enzymes.
Lock-and-Key Model
It allows for small changes in the shape or
geometry of the active site of an enzyme to
accommodate a substrate.
Induced-Fit Model
Factors affecting Enzyme Activity
- Physical Factors
- Chemical Factors
Physical Factors
- Concentration of the Substrate
- Concentration of Enzyme
- effect of pH
- effect of temperature
other
conditions being kept constant, an increase in the
concentration of the substrate will increase the
rate of activity
Concentration of the Substrate
using a highly
purified enzyme, the velocity of the reaction is
directly proportional to the concentration of the
enzyme.
Concentration of Enzyme
each enzyme requires a definite
pH zone. This has been discussed under
characteristics of enzyme action
effect of pH
for each enzyme,
there is an optimum temperature for maximal
activity.
effect of temperature
A phenomenon in which a substrate molecule is
prevented from binding to the active site of
an enzyme by a molecule that is very similar in
structure to the substrate. Thus, the inhibitor
molecule and the substrate that the enzyme
acts on “compete” for the same binding site.
Competitive Inhibition
