Which statement about SpxB and hydrogen peroxide production is correct?

Which statement about SpxB and hydrogen peroxide production is correct?

• A. Only S. mutans produces hydrogen peroxide
• B. SpxB is involved in hydrogen peroxide production in some streptococci
• C. Hydrogen peroxide produced only in anaerobic conditions
• D. Hydrogen peroxide production does not involve SpxB

Answer: (B)

SpxB encodes a pyruvate oxidase that uses oxygen to convert pyruvate into acetyl phosphate and CO2, releasing hydrogen peroxide in the process. This activity isn’t limited to just one species; several Streptococcus species that carry SpxB can produce H2O2, so the idea that SpxB is involved in hydrogen peroxide production in some streptococci is correct. Hydrogen peroxide production in these bacteria depends on oxygen, so it’s not produced only under anaerobic conditions. Additionally, since SpxB is the enzyme responsible for this H2O2 generation in those species, saying it does not involve SpxB isn’t accurate. And it’s not true that only S. mutans makes hydrogen peroxide—other streptococci with SpxB can too.

SpxB encodes a pyruvate oxidase that uses oxygen to convert pyruvate into acetyl phosphate and CO2, releasing hydrogen peroxide in the process. This activity isn’t limited to just one species; several Streptococcus species that carry SpxB can produce H2O2, so the idea that SpxB is involved in hydrogen peroxide production in some streptococci is correct. Hydrogen peroxide production in these bacteria depends on oxygen, so it’s not produced only under anaerobic conditions. Additionally, since SpxB is the enzyme responsible for this H2O2 generation in those species, saying it does not involve SpxB isn’t accurate. And it’s not true that only S. mutans makes hydrogen peroxide—other streptococci with SpxB can too.