Purification of a proteinase and proteinase inhibitor from Tetrahymen a pyriformis

• 1.1. A cysteine proteinase and cysteine proteinase inhibitor have been purified from Tetrahymena.
• 2.2. The proteinase was purified by ammonium sulphate fractionation, gel filtration, ion exchange chromatography and affinity chromatography, and appeared homogeneous by gel filtration and electrophoresis (mol. wt approx 28,000). It hydrolysed BAPNA, degraded azocasein, and converted 80S ribosomes to subunits. Thiol reagents inhibited these activities.
• 3.3. The inhibitor was purified by heat treatment, ammonium sulphate fractionation and ion exchange chromatography, and appeared homogeneous by gel filtration and electrophoresis (mol. wt approx 12.500). The inhibitor was heat stable and it inhibited papain, as well as the Tetrahymena proteinase.