What does a positive gelatin hydrolysis test indicate about an organism's enzymatic activity?

What does a positive gelatin hydrolysis test indicate about an organism's enzymatic activity?

• A. Ability to produce gelatinase to liquefy gelatin; a liquid medium indicates a positive result.
• B. Production of amylase with clear zones around starch.
• C. Proteolysis of casein in skim milk.
• D. Fermentation of gelatin as a carbon source.

Answer: (A)

The key idea is detecting whether an organism makes gelatinase, an enzyme that hydrolyzes gelatin. Gelatin solidifies at cooler temperatures, forming a gel, but if gelatinase is produced, it breaks down the gelatin in the medium. After incubation, the tube is cooled; a positive result shows a liquid medium because the gelatin has been hydrolyzed, indicating gelatinase activity. A negative result would leave a solid gel because no gelatin breakdown occurred. This test is specific to gelatinase activity and not about amylase acting on starch, proteolysis of casein in milk, or fermentation of gelatin as a carbon source, which involve different substrates and enzymes.

The key idea is detecting whether an organism makes gelatinase, an enzyme that hydrolyzes gelatin. Gelatin solidifies at cooler temperatures, forming a gel, but if gelatinase is produced, it breaks down the gelatin in the medium. After incubation, the tube is cooled; a positive result shows a liquid medium because the gelatin has been hydrolyzed, indicating gelatinase activity. A negative result would leave a solid gel because no gelatin breakdown occurred.

This test is specific to gelatinase activity and not about amylase acting on starch, proteolysis of casein in milk, or fermentation of gelatin as a carbon source, which involve different substrates and enzymes.