Proteases, host organisms

It is sometimes necessary to remove an undesirable side activity from proteins and enzymes, particularly when it is not feasible to delete the side activity genetically. A case in point is the presence of co-secreted proteases. Even if minor protease contamination from the host organism does not cause significant... 

The host organism A o/yzae is non-pathogenic and has a long history of use in food. Enzyme preparations from A. oryzae have been evaluated previously by the Committee. For a-amylase and protease from A. oryzae, the Committee concluded that, since they are derived from a microorganism that is accepted... 

All of the preceding techniques are extensively used for the production of detergent enzymes such that today the vast majority of industrial enzymes are produced by recombinant techniques. This is done in a limited number of optimized, well-known production hosts. Some of the most frequently used host organisms are the Bacillus species—B. subtilis, B. licheniformis, and B. clausii, which are used for production of proteases and amylases. The lipases and cellulases of fungal origin are produced by cultivation of the filamentous fungi Aspergillus oryzae and Trichoderma reesei. 

Digestion of host cytosol within the food vacuoles appears to be essential for parasite growth. Treatment of the parasite cultures with inhibitors of the major cysteine protease blocks parasite proliferation (59). This appears to be the result of action within the food vacuole, since the organisms show abnormal vacuole morphology and undigested hemoglobin. The antimalarial drug cloroquine also probably acts at the level of the food vacuole. 

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