Members of this subfamily are probable C-S lyases from a family of pyridoxal phosphate-dependent enzymes that tend to be (mis)annotated as probable aminotransferases. One member is PatB of Bacillus subtilis, a proven C-S-lyase. Another is the virulence factor cystalysin from Treponema denticola, whose hemolysin activity may stem from H2S production. Members of the seed alignment occur next to examples of the enzyme 5-histidylcysteine sulfoxide synthase, from ovothiol A biosynthesis, and would be expected to perform a C-S cleavage of 5-histidylcysteine sulfoxide to leave 1-methyl-4-mercaptohistidine (ovothiol A).
Jiyao W et al.(2023). "The conserved domain database in 2023.",