Metabolism

• organic compounds:

  A) Alcohol

  B) Aldehyde

  C) ketone

  D) Carboxylic Acid

  E) thiol (sulfhydryl)

  F) Amines

  
• Functional groups: Groups of atoms that determine the properties of a molecule.

  A) hydroxyl

  B) acyl

  C) carbonyl

  D) carboxylate

  E) thiol (sulfhydryl)

  F) amino

  G) phosphate

  H) Phosphoryl

  
• Linkages:

  A) phenyl

  B) ether

  C) ester

  D) amide

  E) phosphate ester

  F) phosphoanhydride

  
• •Isomerisation–Switching between isomers of a molecule.
• •Decarboxylation–Removal of carboxyl groups and release of CO2.
• Electron carriers: NAD+

  
• Catabolic: Degrade large molecules into small molecules and energy
• anabolic: to synthesise macromolecules using smaller molecules and energy
• cofactors- metal ions or coenzymes that can be organic or inorganic and assist enzymes in metabolic catalysis
• coenzymes are non protein, organic molecules that are soluble in water when phosphorylated.

  • Bind apoenzymes to proteins to produce active holoenzymes.
• Kinase- adds a phosphate group to a molecule

  phosphatase- removes a phosphate group from the molecule

  isomerase/ mutase- interconverts between two isomers

  dehydrogenase- removes a hydrogen atom

  reductase/ oxidase - performs redox reactions.
• In non-competitive inhibition, an inhibitor molecule binds to the enzyme at a location other than the active site (an allosteric site). The substrate can still bind to the enzyme, but the inhibitor changes the shape of the enzyme so it is no longer in optimal position to catalyse the reaction.
•  Allosteric inhibitors and activators: Allosteric inhibitors modify the active site of the enzyme so that substrate binding is reduced or prevented. In contrast, allosteric activators modify the active site of the enzyme so that the affinity for the substrate increases.
• In noncompetitive allosteric inhibition, inhibitor molecules bind to an enzyme at the allosteric site.

  • Their binding induces a conformational change that reduces the affinity of the enzyme’s active site for its substrate.
  • The binding of this allosteric inhibitor changes the conformation of the enzyme and its active site, so the substrate is not able to bind.
  • This prevents the enzyme from lowering the activation energy of the reaction, and the reaction rate is reduced.
• Allosteric activators can increase reaction rates. They bind to an allosteric site which induces a conformational change that increases the affinity of the enzyme’s active site for its substrate. This increases the reaction rate.
• Cofactors are inorganic ions such as iron (Fe2+) and magnesium (Mg2+). For example, DNA polymerase requires a zinc ion (Zn2+) to build DNA molecules.
• Vitamin C is a coenzyme for multiple enzymes that take part in building collagen, an important component of connective tissue.
• Feedback inhibition prevents the production of additional ATP if it is already abundant as ATP inhibits the same enzymes that produced it, ADP is an allosteric activator. When levels of ADP are high compared to ATP levels, ADP triggers the catabolism of sugar to produce more ATP.
• Feedforward activation is a regulatory process in enzyme pathways. In feedforward activation, a metabolite produced early in a pathway activates an enzyme that catalyses a reaction further down the pathway.