PURIFICATION, MOLECULAR-PROPERTIES AND SPECIFICITY OF A THERMOACTIVE AND THERMOSTABLE PROTEINASE FROM PYROCOCCUS-ABYSSI, STRAIN ST-549, HYPERTHERMOPHILIC ARCHAEA FROM DEEP-SEA HYDROTHERMAL ECOSYSTEM

A protease was isolated and purified from the supernatant of a culture of hyperthermophilic archaebacteria: Pyrococcus abyssi strain st 549. Purification consisted of three chromatographic steps. The enzyme pur ification yield was 4% and the purification factor 890, This protease is a seryl-protease hydrolyzing proteins and peptides with a preferenc e for cleavage at the aromatic and hydrophobic residues in P1 and P'1 positions. Its activity is optimal at 95 degrees C and at pH 9, The el ectrophoretic mobility of the protease observed by zymogram suggests t hat it can adopt several oligomer forms. Three of them predominate dis playing apparent molecular masses of 150, 105 and 60 kDa. Interdepende nce of the observed bands was revealed by changing the denaturation co nditions of the samples (temperature, SDS concentration) before electr ophoresis, (C) 1998 Federation of European Biochemical Societies.