A novel thermostable protease was purified from Penaeus vannamei from Persian Gulf to homogeneity
level using ammonium sulfate precipitation and anion-exchange chromatography. The purified protease
showed a single band on native and SDS–PAGE with a molecular weight of 24 kDa on SDS–PAGE. The
enzyme showed the broad highest catalytic activity for hydrolysis of the substrate with maximal activity
at pH 7 and 80 C. Activity of the enzyme was inhibited by Hg2+, Zn2+ Co2+ and Cu2+, while protease activity
was increased in the presence of Fe2+ and Mn2+ by factors of 173% and 102%, respectively. Enzyme
shows a broad substrate specificity and hydrolyzes both natural and synthetic substrates. Based on the
Michaelis–Menten plots, the Km with casein as substrate was 16.8 lM and Vmax was 82.6 lM/min. The
enzyme, derived from L. vannamei, possesses unique characteristics and could be used in various industrial
and biotechnological applications.