FIG 3.
Countersubstrate specificities of rEhMCF reconstituted in vesicles. The substrate-loaded vesicles (preloaded substances are indicated by names) and the empty vesicles (indicated by a minus sign) were assayed for the uptake of either [32P]ATP (A) or [35S]PAPS (B). The specific transport activity (A) and the transport activity relative to that of PAPS as the control (set as 100%) (B) are shown. The data are presented as the means ± SDs calculated from the results of three independent experiments. The raw data used to calculate the relative activity levels are as follows: PAPS, 32.8 ± 7.2; PAP, 39.1 ± 13.9; ATP, 14.1 ± 5.0; ADP, 13.6 ± 3.2; AMP, 2.4 ± 0.7; APS, 7.3 ± 1.6; CoA, 4.2 ± 0.7; sulfate, 0.1 ± 0.1; GTP, 0.1 ± 0.2; −, 0.0 ± 0.1 (nmol/mg protein/min). Asterisks indicate significant differences between PAPS and other countersubstrates (*, P < 0.05; **P < 0.01).