Production,purification,and characterization of a novel thermostable serine protease from soil isolate,Streptomyces tendae

摘要

An isolate of Streptomyces tendae produced a extracellular protease which was purified to apparent homogeneity giving a single band on SDS-PAGE with a molecular mass of 21 kDa.Optimum activity was at 70 deg C and pH 6.It was stable at 55 deg C for 30 min and between pH 4 and 9.It was resistant to neutral detergents and organic solvents such as Triton X-100,Tween 80,methanol,ethanol,acetone,and 2-propanol at 5% (v/v).The enzyme was completely inhibited by 5 mM PMSF,indicating it to be a serine protease.N-Terminal amino acid sequence did not show any homology with other known proteolytic enzymes.The protease may therefore be a novel neutral serine protease,which is stable at high temperature and over a broad range of pH.