Metallo thermolysin

M. anisopliae thermolysin thermolysin-like metallo 43 7.3 1,10-phenanthioline, phosphoramidon St. Leger et al. (1994a)... 

Thermolysin is a zinc metallo enzyme which binds Ca2+ ions. It consists of a single polypeptide chain of M.W. 34600 containing 316 amino acid residues. Four Ca2+ ions per molecule give thermal stability to the enzyme. The crystal structure of both Ln3+ substituted and unsubstituted enzyme has been determined [54],... 

Another example of a protease-catalyzed commercial process, which in this case uses the enzyme in a synthetic mode, is the completely regio- and stereoselective production of the low-caloric sweetener aspartame developed by DSM-TOSOH [15] (Fig. 7.9). Aspartame is a dipeptide consisting of the amino acids phenylalanine and aspartic acid, which are coupled by the enzyme thermolysin from Bacillus thermoproteolyticus. For an efficient coupling, relatively high temperatures are required and the amount of water in the system must be kept low to drive the reaction in the desired direction. Thermolysin, which is a metallo-endoprotease, meets these two requirements. It is thermostable, and it works in an organic solvent, which is required to keep the water activity low. In practice, however, organic solvents were not necessary, since the product aspartame forms an insoluble complex with unreacted D-Phe-OMe, which crystallizes out of the aqueous medium. 

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