Metal Ion Catalysis PPT | Enzyme Catalytic Mechanisms | Approximation Strain and Distortion

Once a substrate is bound to an enzyme, properly positioned catalytic functional groups aids in the cleavage and formation of bonds by a variety of mechanisms, including:

Metal ion catalysis ​

• Nearly a third of all known enzymes require one or more metal ions for catalytic activity​
• Metals, either as prosthetic group tightly bind to the enzyme or as transiently bind to the enzyme at the time of reaction can participate in catalysis in several ways:​
  • Metal ions can serve as electrophilic catalyst, stabilizing negative charge on a reaction intermediate.​
  • Stabilize transition state and reactive intermediates.​
  • Act much like a proton but can be present in high concentration at neutral pH and can have multiple positive charges.​
  • Help to generate strong nucleophile group.​
  • Bind to substrates to insure proper orientation.​
  • Metals can mediate oxidation-reduction reactions by reversible changes in the metal ion’s oxidation state.​

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