extremely Thermophilic Bacterium

Proteasescomprisea significant proportion of thoseproteins which have been subject to detailedcharacterisationaminoacid sequenceand high resolulion crystallographic analysis. The extent of researchinterest in proteolytic enzymes reflects both theirhistorical status, and the practical advantages of pro-teases as research subjects available in quantity, extrace lutar etc. widely occurring.Since 1952, a variety of proteases from thermophilicorganismshavebeen isolated andcharacterised. In par.licular, the extracellular protease Thermolysin fromBacillus thermoproteolytious has been subjected tonumerous detailed kinetic1 and structural studies2.However,to date, there have been noextensive studieson proteolytic enzymes from extreme thermophiles,althougha numberof reportsoftheirexistencehaveappeared3'4. Thework reported here on Caldolysin, the extracellularproteasefromtheextremethermophile, Thermus aquaticus strain