Question

LABORATORY REPORT Part 2 rotein Catabolism, PURPOSE HYPOTHESES color in Phenylalanine deaminase is indicated by a(n) . Cysteine desulhydrase is indicated by atn . color in Ornithine decarboxylase is indicated by aln) ESULTS l in the following table MIO Test Phenylalanine Deaminase Hydrogen Sulfide Indo Motility Original color:ngcOriginal color Original color: Cca Reaction Reaction Motility Color +or-) Growth lorGrowth rganism Growth Color cherichia Not tested Not t oteus

Answer 1

Purpose:

In bacteria, the protein catabolism involves secretion of exoenzymes which are involved in the breakdown of amino acids and other small compounds. Different bacteria metabolize different amino acids and also they vary in metabolizing their by-products. This property is used to differentiate enteric bacteria using various protein catabolism tests.

Hypotheses:

• Phenylalanine deaminase is indicated by a dark green color in phenylalanine deamination test.
• Cysteine desulfhydrase is indicated by a black color in H₂S production test.
• Ornithine decarboxylase is indicated by a red color in the MIO (Motility Indole Ornithine) test.

Result:

Organism:

Test 1: Phenylalanine deaminase.

Original color: Yellow

Organism	Growth	Color	Reaction (+ or -)
Escherichia coli	present	remains yellow	-ve
Proteus sp.	present	the appearance of dark green	+ve

Test 2: Hydrogen sulfide.

Original color: straw to yellow color

Organism	Growth	Color	Reaction (+ or -)
Escherichia coli	present	no black	- ve
Proteus sp.	present	black	+ve