TABLE 1.

R_f values of flavins by ascending thin-layer chromatography^a

Solvent system	Rf value
	Flavin standard			rNoxA2 cofactor
	FMN	Riboflavin	FAD
A	0.56	0.29	0.39	0.41
B	0.29	0.48	0.11	0.13
C	0.40	0.63	0.25	0.23

^aSamples were separated on Whatman no. 1 paper for solvents A and B and on Silica Gel 60 plates for solvent C. Cofactor was released by TCA extraction for rNoxA2 (30 μg) for solvent A, heat extraction from rNoxA2 (60 μg) for solvent B, and hot methanol extraction from rNoxA2 (7 μg) for solvent C. Solvent system A was 5% disodium hydrogen phosphate in H₂O. Solvent system B was n-butanol–acetic acid–H₂O (4:1:5). Solvent system C was n-butanol–acetic acid–H₂O (12:3:5).