Abstract: A method for making a stabilized neutral metalloprotease enzyme composition is described in which a neutral metalloprotease and an aqueous solution are combined to obtain a solution or slurry thereof, whereby the stabilized neutral metalloprotease enzyme composition is obtained. The aqueous solution contains an N-protected amino acid, or an N-protected amino acid is added thereto. The invention also provides a stabilized neutral metalloprotease composition, and a method of transporting the stabilized neutral metalloprotease composition.

Abstract: The invention relates to a process for the preparation of N-protected-L-aspartyl-L-phenylalanine methyl ester by enzymatic coupling of an N-protected-L-aspartic acid and L- or DL-phenylalanine methyl ester in an aqueous solution with formation of a precipitate using a thermolysin-like protease enzyme, wherein a water-immiscible organic solvent is added to and blended with the reaction system during the formation of the precipitate in the course of the coupling reaction, which organic solvent has a relatively high affinity for the precipitate. The process is particularly suitable as a continuous process. The method results in lower enzyme deactivation during and after the enzymatic coupling reaction and in larger and thicker precipitated crystals.

Abstract: A method for crystallizing .alpha.-L-aspartyl-L-phenylalanine methyl ester from a hot aqueous solution containing .alpha.-L-aspartyl-L-phenylalanine methyl ester by cooling is disclosed, which comprises (i) continuously supplying a hot aqueous solution of .alpha.-L-aspartyl-L-phenylalanine methyl ester having a concentration such that the content of L-aspartyl-L-aspartyl-L-phenylalanine methyl esters is less than 0.6% by weight based on the weight of .alpha.-L-aspartyl-L-phenylalanine methyl ester in said solution, or if the content of L-aspartyl-L-aspartyl-L-phenylalanine methyl esters is 0.6% by weight or more based on the weight of .alpha.-L-aspartyl-L-phenylalanine methyl ester in said solution, to a crystallization vessel the temperature of which is lowered to that corresponding to the solubility of .alpha.-L-aspartyl-L-phenylalanine methyl ester or less, and (ii) continuously discharging the formed slurry from the crystallization vessel.