Subcellular localization of glucose-6-phosphate dehydrogenase (G6PD) in the bovine coronary artery (BCA). A: ultracentrifugation of the endothelium and adventitia removed BCA homogenate was performed to separate microsomal and cytosolic fractions. The microsomal fraction was further separated on a Ficol gradient, and Western blot analyses of the caveolae fractions were conducted using 4–12% gel and monoclonal anti-Na+-K+-ATPase, anti-caveolin-1 (CAV1), and polyclonal anti-G6PD antibody, respectively. LDH was used as a cytosolic marker. The caveolae G6PD migrated slower than the cytosolic G6PD. Representative Western blot of 5 separate experiments is shown. B: the graph represents the G6PD activity measured in the nucleus (fraction 2), mitochondria plus large organelles (fraction 3), submitochondrial particles plus small organelles (fraction 4) and cholesterol-rich caveolae (in yellow box; fraction 5), and cytosolic (fraction 6) fractions. C: the graph represents NADPH levels in the caveolae (triangle) and cytosolic (square) fractions of CAs; n = 20 observation from 5 separate experiments in each group.