Protein Catabolism

Question 1

What is the Lysine Decarboxylase test used for?

Answer 1

If bacteria produces decarboxylase
Differential agent: amino acid lysine
Ph indicator: bromocresol purple (high pH)
Positive test result: purple. Negative test result: yellow (low pH)
Use mineral oil to encourage fermentation/reduce oxygen
Breaks down into cadaverine

Question 2

What does phenylalanine deanimase test for?

Answer 2

-the enzyme deanimase
-differential material is the amino acid phenylalanine
-reagent added AFTER fermentation called ferric Chloride
-Major products are phenylpyruvic acid and ammonia
-if phenylpyruvic acid is produced, turns green

Question 3

Name the Important facts about the Urease Test.

Answer 3

Differential ingredient: urea
Enzyme tested for: urease
PH indicator: phenol red
Positive result: bright pink (product: ammonia)
Negative result: yellow (low pH)

Question 4

Name the important facts about the S part of the SIM test

Answer 4

Differential ingredients: Cysteine and thiosulfate
Enzymes: cysteine desulfhydrase and/or thiosulfate reductase
Positive result: black (hydrogen sulfide (H2S))

Question 5

What is the differential agent in the lysine decarboxylase test?

Answer 5

Lysine (an amino acid)

Question 6

What is the pH indicator in the lysine decarboxylase test?

Answer 6

Bromocresol purple.

Question 7

What is a positive result of the lysine decarboxylase test?

Answer 7

Purple (signifying high pH)