Active transport of sulfates in membranes isolated from Bacillus subtilis
Cacco, G.; Civelli, G.
Bollettino della Societa Italiana di Biologia Sperimentale 51(3): 106-111
1975
ISSN/ISBN: 0037-8771 PMID: 807226 Document Number: 83584
Membranes of B. subtilis were isolated from strain 168 try of Rothman using lysozyme in hypertonic solution to remove the cytoplasm. The washed membranes were treated with 35S labeled K2SO4 (10-6M) with a specific activity of 50 .mu.Ci/meq. Transport of sulfate was blocked at intervals by dilution and rapid filtration on Millipore HA 0.45 and the radioactivity was counted. The membrane vesicles were capable of actively transporting SO42- and retained 6% of the original radioactivity of the solution. Transport increased with temperature, exceeding 6% at 30.degree. C after 25 min. The transport reached a plateau at 30-40 min. The sulfate uptake is comparable to that of living bacterial cells except that continuing metabolism to sulfur amino acids characteristic of the living cell does not continue.