Novel alkaline- and heat-stable serine proteases from alkalophilic Bacillus sp. strain GX6638.

摘要: An alkalophilic Bacillus sp., strain GX6638 (ATCC 53278), was isolated from soil and shown to produce a minimum of three alkaline proteases. The proteases were purified by ion-exchange chromatography distinguishable their isoelectric point, molecular weight, electrophoretic mobility. Two the proteases, AS HS, which exhibited greatest thermal stability, characterized further. Protease HS had an apparent weight 36,000 point approximately 4.2, whereas protease 27,500 5.2. Both enzymes optimal proteolytic activities over broad pH range (pH 8 12) temperature optima 65 degrees C. Proteases further distinguished activities, esterolytic sensitivity inhibitors, stability properties. extremely alkali stable, retaining 88% initial activity at 12 24-h incubation period 25 C; similar properties 11. In addition, exceptional At 9.5 (0.1 M CAPS buffer, 5 mM EDTA), enzyme half-life more than 200 min 50 C 60 above 9.5, readily lost enzymatic even in presence exogenously supplied Ca2+. contrast, stable Ca2+ addition extended 10-fold data presented here clearly indicate that these two sp. represent novel differ fundamentally previously described for members genus Bacillus.