Heterogeneity of proteinases from the hyperthermophilic archaeobacterium Pyrococcus furiosus
Intracellular and extracellular samples from the extremely thermophilic archaeobacterium Pyrococcus furiosus showed the presence of multiple active proteinases. Using gelatin-containing SDS-PAGE, up to 13 activity bands were visualized with apparent molecular masses of between 66 and 135 kDa. Characterization studies revealed these bands to be due to discrete polypeptides, and not artefacts. Results from gel permeation chromatography, sucrose density gradient centrifugation and non-denaturing PAGE suggested that some of these proteohtic polypeptides may exist as active aggregates either in vivo or in vitro before being dissociated by SDS to active monomers.