... shown in Fig. 2. Several proteinsare visible in regions of the second dimension that cor-respond to the activity bands in the BN gel. Five pro-tein spots from the upper band, corresponding to the high ... arrows).Owing to the horizontal smear, however, the presence of the B14 subunit in the lower band cannot be ascer-tained at this point. A cross-reaction of the antibodyagainst the 39 kDa subunit of ... access the flavin cofactor in the large form of complex I,whereas the cofactor remains accessible in the smallform. Indeed, to address this possibility, experimentswith prolonged preincubation...