Fig. 2. Gel filtration of recombinant and native MsGC-ß3. Supernatants from extracts of COS-7 cells that had been transiently transfected with either MsGC-ß3 (solid line), MsGC-ß3C338 (broken line) or nerve cords (CNS; dotted line) were homogenized in 50 mmoll^-1 Tris HCl, pH 7.5 and separated by gel filtration in the presence of 0.2% octyl ß,D-thioglucopyranoside. Fractions from COS-7 cell extracts were assayed for guanylyl cyclase activity and fractions from nerve cord homogenates were assayed by western blot. Molecular mass estimates were generated by comparing with standard proteins run in parallel.