The endogenous substrate is not known. In vitro, catalyzes the H(2)O(2)-dependent epoxidation of styrene, cis-beta-methylstyrene, and cis-stilbene with retention of stereochemistry. Is able to use cumene hydroperoxide (CHP) or tert-butyl hydroperoxide (TBHP) instead of H(2)O(2) as the electron acceptor. Can also hydroxylate fatty acids such as lauric acid. 2 a phenolic donor + H2O2 = 2 a phenolic radical donor + 2 H2O Binds 1 heme group per subunit. Optimum pH is 8.5 for peroxidase activity. Optimum temperature is about 75 degrees Celsius. Activity is 10-fold greater at 75 degrees Celsius than that measured at 25 degrees Celsius. Thermostable up to 85 degrees Celsius. Thermal denaturation midpoint (Tm) is 91 degrees Celsius. Belongs to the cytochrome P450 family. Was originally (PubMed:8617361) thought to originate from Sulfolobus solfataricus, but was shown (PubMed:18157853) to stem from Sulfolobus acidocaldarius. This was due to a contamination of the S.solfataricus P1 strain isolate used for the initial cloning with the S.acidocaldarius species.