Topic 15: Protein Catabolism

amino acid

The ability of some bacteria to convert the ________ tryptophan to indole or a blue compound indigo is a useful diagnostic tool.

amino acid

Presence of a specific decarboxylase enzyme results in the breakdown of the ________ with the formation of the corresponding amine, liberation of carbon dioxide, and a shift in pH to alkaline.

amino acid

Before ________ can be used as carbon or energy source, the amino group must be removed.

Protein

large organic molecules that include cellular enzymes and many strutures

Amino acids

subunits that make up a protein; consist of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur

Deamination

removal of an amino group

Decarboxylation

removal of carbon dioxide from an amino acid

Some bacteria liberate hydrogen sufide (H2S) from the sulfur-containg amino acids

cystine, cystein, add methionine

To detect H2S production

a heavy metal salt containing ferrous ion (Fe 2+) is added to nurtient culture medium

When H2S produced

black precipitate forms

Motility indole ornithine (MIO) agar used

detects motility, indole production, and ornithine decarboxylase activity

What is a protein?

large organic molecule that include cellular enzymes and many structures

What are amino acids?

subunits that make up a protein; consist of carbon, hydrogem, oxygen, nitrogen, and sometimes sulfur

How does amino acids bond together?

peptide bonds

What is a small chain of amino acids?

peptide

What is a large molecule of amino acids?

polypeptide

What can be used as a carbon or energy source when carbohydrates are not available?

amino acids

Amino acids are primarily used in ___ reaction.

anabolic

Gelatin is a ___ that is hydrolyzed by ____.

large protein; exoenzymes

Why must nutrient gelatin be incubated at room temperature?

will liquify in incubator

What is a waste product of protein digestion and is excreted in the urine?

urea

What enzyme breaksdown urea to ammonia?

urease

What must occur to amino acid before it can be used as carbon or energy source?

amino group or carbon dioxide must be removed

What is deamination?

removal of an amino group from amino acid

Amino group is converted to ___ during deamination.

ammonia

What is decarboxylation?

removal of carbon dioxide from an amino acid

Some bacteria can liberate ___ from sulfur containing amino acids.

hydrogen sulfide (H2S)

Some bacteria can convert amino acid tyrptophan to ___.

indole