Biotin (S)-sulfoxide is an inactive metabolite of the coenzyme biotin .1,2 It has also been found in E. coli and is reduced by the biotin sulfoxide reduction system as a source of biotin.3
1.Denkel, L.A., Rhen, M., and Bange, F.-C.Biotin sulfoxide reductase contributes to oxidative stress tolerance and virulence in Salmonella enterica serovar TyphimuriumMicrobiology (Reading)159(Pt 7)1447-1458(2013) 2.Carling, R.S., and Turner, C.Methods for assessment of biotin (Vitamin B7)Laboratory assessment of vitamin status193-217(2019) 3.del Campillo-Campbell, A., Dykhuizen, D., and Clearly, P.P.Enzymic reduction of d-biotin d-sulfoxide to d-biotinMethods Enzymol.62379-385(1979)