Dynamics of accumulation of proteolytic activity during growth of cultures П1 and Ц3 depending on a
source of nitrogen has been studied. Cultures are allocated from ground deposits of hydroterms Goryachinsk and sodasaline
lake Solenoe. Strains actively produce protease, which hydrolyze a specific for subtilizinlike proteinases synthetic
substratum GААLP, the greatest activity is observed on 24 h growth of cultures. Protease are stable at temperature
40–50 ^oС and рН 6,0–11,3. Inhibit analysis has shown, that at addition up to 1 mM FMSF the full inhibition of
proteolytic activity is observed. Data of the inhibit analysis and substrate specificity of the most active extracellular
protease of the strains П1и Ц3 indicate to their accessory to a class of serine protease of the subtilizinlike type.