Which of the following is true about Streptolysin S?

Streptolysin S is a hemolysin produced by certain strains of Streptococcus bacteria, particularly Streptococcus pyogenes. One of the key characteristics of Streptolysin S is that it is oxygen stable, meaning it can function in the presence of oxygen. However, its activity is maximized under anaerobic conditions, where it can effectively lyse red blood cells and other cells. This enhanced activity under low-oxygen environments is crucial for its role in the pathogenicity of the bacteria, particularly in the human body, where microenvironments may have varying levels of oxygen.

This understanding clarifies its importance in both clinical settings and microbiological studies, as well as its ability to facilitate the infection process in certain tissues. In contrast, the other options do not accurately represent the capabilities or characteristics of Streptolysin S, reinforcing the significance of its function in anaerobic environments.