Members of this family, found primarily in the genus Streptococcus, were shown to be L-lactate dehydrogenase (quinone) (Lqo) although they have generally been misannotated as malate dehydrogenase (quinone). Staphylococcus can survive nitrous oxide exposure from host defense through a response in which L-lactate is excreted in large amounts. Lqo acts in L-lactate consumption after its reuptake.
Jiyao W et al.(2023). "The conserved domain database in 2023.",