Table 3.

Endogenous FMO substrates

Substrate	FMO	Km (μM)	Product	Reference
Sulfur-containing
Cysteamine	pFMO1a	120	Disulfide	Poulsen, 1981
	hFMO2	175		Unpublished
S-cysteine conjugates	pFMO1	344–1538	S-oxide (diastereometric excess 10–78%)	Park et al., 1992
S-allyl-l-cysteine	Rat in vivo		Sulfoxide	Krause et al., 2002
S-farnesylcysteine and	pFMO1			Park et al., 1994
S-farnesylcysteine methyl ester		23–34	S-oxide	Park et al., 1994
Dihydrolipoic acid and	pFMO1	1700		Taylor & Ziegler, 1987
Lipoic acid	pFMO1	120		Taylor & Ziegler, 1987
	hFMO2	71		Unpublished
Methionine	hFMO3	20,000	(d>l)-sulfoxide	Ripp et al., 1999
	rat FMO3	3400	(d>l)-sulfoxide	Krause et al., 1996
	Rabbit FMO1	48,000	(d/l=1.5)-sulfoxide	Duescher et al., 1994
	Rabbit FMO2	30,000	(d/l=0.7)-sulfoxide
	Rabbit FMO3	6500	(d/l=8)-sulfoxide
Nitrogen-containing
Trimethylamine	hFMO3	28	N-oxide	Lang et al., 1998
	pFMO1	617		Sabourin & Hodgson, 1984
	Mouse liver FMO	2340		Sabourin & Hodgson, 1984

^ap = Pig; h = human.