Control METABOLISM Metabolic reactions can be controlled and sped up by enzymes metabolic...
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Transcript of Control METABOLISM Metabolic reactions can be controlled and sped up by enzymes metabolic...
Control METABOLISM Metabolic reactions can be
controlled and sped up by enzymes metabolic reactions would be
too slow to occur if no enzymes were present!
End in “ase”
Properties of Enzymes1.Proteins2.Catalysts3.Reusable 4.Substrate
specific5.Sensitive to
temperature6.Sensitive to
pH
Enzymes Remain Unchanged! Enzymes are not
used up; Reaction ends when there is NO MORE SUBSTRATE!!
Synthesis or Decomposition reactions
substrate
enzyme
active site
substrate
Mechanism of Enzyme ActionMechanism of Enzyme Action• Each enzyme has an ACTIVE SITE!!• Active site is the place where the
substrate binds with the enzyme
enzyme
Action of Enzyme in Action of Enzyme in SynthesisSynthesis
substrate
substrate
enzyme-substrate complex
Product and
enzyme
Action of Enzyme in Action of Enzyme in DecompositionDecomposition
substrate
enzyme-substrate complex
product
Lock and Key Hypothesis
Enzyme
Substrate
Lock and Key Hypothesis
SHAPES
DON’T
MATCH
Lock & Key Model ONE enzyme for every substrate
Unique fit
Enzyme
Substrate
Enzymes are Temperature Dependent…...
Most work BEST at body temperature
37oC DENATURE at high
temperatures
Inactive at LOW temperature
Effect of pH on Enzyme Activity
Optimum pH : the pH value at which the enzyme has the highest activity (fastest rate of reaction)
--Different enzymes may have different optimum pH’sDifferent enzymes may have different optimum pH’s
-If pH is higher or lower than optimum pH, -If pH is higher or lower than optimum pH, denaturation happens; enzyme becomes ineffective.denaturation happens; enzyme becomes ineffective.
What pH does pepsin work best?
What pH does pancreatic lipase work?
Enzyme Lab Enzyme: catalase Source: liver, potato,
apple etc Substate:H2O2(Hydrogen
Peroxide)
Hydrogen peroxide is toxic in cells
2H2O2 +catalase 2 H2O + O2