An extracellular serine alkaline protease produced by Bacillus sp. SSR1 was purified to homogeneity by Sephadex A-50 and Sepharose 6B column chromatography. The enzyme is a monomeric protein with a molecular weight of 29 and 35 kDa as estimated by SDS-PAGE and native PAGE respectively. The purified enzyme is stable in the alkaline pH range (8.0-11.0) and retains 100% activity at its optimum temperature of 40 degreesC even after 300 min of incubation. The presence of CaCl2 shifts the optimum temperature to 45 degreesC and produces a 1.3-fold increase in its activity. The enzyme remains active and stable in various detergents and is strongly activated by metal ions (Fe3+. Ca2+, Na+)