Catalase Test- Scope, Principle, Procedure, Uses and Results and Interpretation
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Scope To detect the catalase enzyme present in most cytochrome-containing aerobic and facultatively anaerobic bacteria. It is used to differentiate those bacteria that produce an enzyme catalase, such as staphylococci, from non-catalase producing bacteria such as streptococci. Principle Catalase is an enzyme that breakdown hydrogen peroxide (H2O2) into water and oxygen. The catalase is a hemoprotein, similar in structure to hemoglobin, except that the four iron atoms in the molecule are in the oxidized (Fe3+), rather than the reduced (Fe2+), state. Excluding the streptococci, Enterococci, and a few other genera, most aerobic and facultative bacteria possess catalase activity. Hydrogen peroxide forms as one of the oxidative end products of aerobic carbohydrate metabolism. If allowed to accumulate, it is lethal to bacterial cells. Catalase converts hydrogen peroxide into oxygen and water as shown by the following reaction: 2H2O2 → 2H2O + O2 (Gas bubbles Appe...