Inhibition of vitamin K2 and carotenoid synthesis in Staphylococcus aureus by diphenylamine.

Diphenylamine at concentrations which did not effect the growth rate inhibited the synthesis of vitamin K(2) in both anaerobic and aerobic cultures by about 50%. At this concentration, diphenylamine inhibited the synthesis of the cyclic carotenoids delta-carotene and the rubixanthins 25 to 35% anaerobically and 60 to 90% aerobically. The inhibition of synthesis of cyclic carotenoids and vitamin K(2) by diphenylamine had no detectable effect on the formation of the membrane-bound electron transport system.