Microbiology Lab

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Microbiology Lab
2010-10-08 00:18:42
Lab Bacterial enzymes

Bacterial enzymes
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  1. Bacterial enzymes
    • microorganisms produce a variety of enzymes
    • each enzyme catalyzes specific chemical reaction within the protein
    • the production of specific enzymes are characteristic used to differentiate between organisms
    • some enzymes: urease, catalase, coagulase
  2. Urease
    • this enzyme catalyzes the breakdown of urea into ammonia and carbon dioxide
    • culutre media is phenol red as a pH indicator - acidic
    • when ammonia is released, the pH becomes alkaline causing the indicator to change from peach to dark pink
    • Urea is usually alkaline
    • Urease production is a characteristc of the genus Proteus
  3. Catalase
    • is an enzyme that catalyzes the breakdown of hydrogen peroxide to water and gaseous oxygen
  4. Coagulase
    • the enzyme coagulase causes plasma to clot
    • plasma is the liquid portion of blood
    • Staph a. is the only pathogenic organism that produces coagulase
  5. Catalase +
    is always Staphylococcus
  6. Catalase -
    • is always Streptococcus
    • Remember T in the middle for -
  7. Coagulase +
    is always Staphyloccocus aureus
  8. Coagulase -
    is always Staphyloccocus epidermis
  9. Urease +
    • is alway Proteus
    • usually described as Gram negative rod, urease +