Lecture Notes: Protein Denaturation and Enzyme Function

Protein Denaturation in Children

• Denaturation Temperature

  • Children's proteins do not denature until around 106°F.
  • Protective mechanisms prevent denaturation until higher temperatures.
  • Doctors are usually not alarmed until temperature reaches 106°F.

• Risks of High Temperature

  • Above 106°F, proteins start to denature, potentially causing:
    • Brain damage
    • Cardiovascular damage

Enzymes and Their Functions

General Properties of Enzymes

• Enzymes are globular tertiary proteins.
• Function as catalysts:
  • Speed up chemical reactions.
  • Can be recycled and used repeatedly.
  • Some enzymes can slow down reactions as well.

Enzyme Functionality

• Enzyme Structure

  • Enzymes have specific active sites, similar to magnetic pockets.
  • Enzymes accelerate reactions by bringing substrates into proximity.

• Example Without Enzymes

  • Two molecules (1 cm apart) take 10 years to naturally bond.

• Enzyme Action

  • Enzymes attract specific chemicals to their active sites.
  • Enzymes can change shape to facilitate bonding (occurs in microseconds).

Specificity and Affinity

• Specificity

  • High specificity: Enzyme is picky about substrates.
  • Low specificity: Enzyme is less selective.

• Affinity

  • Enzymes draw in certain chemicals into active sites, known as substrates.

Enzyme Mechanism

• Active Sites and Substrates

  • Active sites bind to specific molecules (substrates).
  • Enzymes change shape using a phosphate (and sometimes cofactors) to bond substrates.

• Cofactors

  • Some enzymes require additional substances (cofactors) like copper or magnesium to function.

• Enzyme Reuse

  • After reaction, enzymes return to original shape and can be reused.

By understanding these enzyme properties and how proteins denature under temperature stress, we gain insights into their critical roles in biological processes.