Acrylamide gel electrophoresis of intracellular proteins during early stages of sporulation in Bacillus subtilis

An improved method for the purification of Bacillus subtilis glucose dehydrogenase cloned in Escherichia coli

An improved and simplified purification procedure has been developed for the isolation of the Bacillus subtilis glucose dehydrogenase which has resulted in a 10 fold higher yield of pure enzyme. The purification procedure utilizes gene cloning and an additional ammonium sulfate step to facilitate the removal of contaminating proteins. The procedure requires fewer chromatographic steps than previously reported, thus simplifying the procedure. This improved and simplified purification of B. subtilis glucose dehydrogenase will facilitate further structure-function studies of this sporulation specific enzyme.

Location and properties of glucose dehydrogenase in sporulating cells and spores of Bacillus subtilis

Late during sporulation, Bacillus subtilis produces glucose dehydrogenase (GlcDH; EC 1.1.1.47), which can react with D-glucose or 2-deoxy-D-glucose and can use nicotinamide adenine dinucleotide (NAD) or nicotinamide adenine dinucleotide phosphate (NADP) as a cofactor. This enzyme is found mainly in the forespore compartment and is present in spores; it is probably made exclusively in the forespore. The properties of GlcDH were determined both in crude cell extracts and after purification. The enzyme is stable at pH 6.5 but labile at pH 8 or higher; the pH optimum of enzyme activity is 8. After inactivation at pH 8, the activity can be recovered in crude extracts, but not in solutions of the purified enzyme, by incubation with 3 M KCl and 5 mM NAD or NADP. As determined by gel filtration, enzymatically active GlcDH has a molecular weight of about 115,000 (if the enzyme is assumed to be globular). GlcDH is distinct from a catabolite-repressible inositol dehydrogenase (EC 1.1.1.18), which can also react with D-glucose, requires specifically NAD as a cofactor, and has an electrophoretic mobility different from that of GlcDH.

Isolation of acetyl esterase mutants of Bacillus subtilis 168

Five mutants of Bacillus subtilis 168 defective in an intracellular esterase activity were identified. By polyacrylamide gel electrophoresis, four of the mutants were shown to lack esterase B activity, and the fifth lacked esterase A activity. All of the back-crossed esterase mutants were able to sporulate at wild-type frequency and produce exoprotease(s) and antibiotic(s). No difference in motility could be attributed to the esterase mutation. PBS1 transduction analysis showed all the esterase B mutations to be linked to the hisA marker.

Characterization of intracellular esterase A from Bacillus subtilis

Esterase A (EC 3.1.1.1) obtained by sonic disruption of Bacillus subtilis SR22 (spoA12, trpC2) was purified approximately 400-fold by differential chemical and heating precipitation, DEAE-cellulose chromatography, and Bio-Rad P-150 gel filtration chromatography, with an overall yield of 59%. The purified enzyme hydrolyzed both aliphatic and aromatic acetate esters at substrate concentrations of 0.25 M but did not hydrolyze amino acid esters. Aliphatic alcohols did not inhibit the hydrolysis of p-nitrophenyl acetate; the most potent inhibitors of esterase activity were mercuric chloride, diisopropylfluorophosphate, eserine, and sodium fluoride.