IMPROVED METALLO-ENDOPEPTIDASES

摘要

The present invention provides genes encoding variants of metalloendopeptidases that have been engineered to be resistant to prolonged boiling while having maintained their enzymatic performance at much lower temperatures. In addition, thermal stability of the metallo-endopeptidases is highly dependent on calcium at concentrations in the mM range. The invention further provides active metallo-endopeptidases variants whose stability depending on calcium concentration can be changed so as to provide metalloendopeptidases that are calcium dependent or independent. The invention also provides genes that encode boiling-resistant metallo-endopetidases whose stability depending on calcium concentration can be changed. The invention also provides vectors and cells comprising these genes and proteases produced through these genes, vectors and/or cells. In particular variants with the above described properties are provided of thermolysin-like proteases such as produced by Bacillus stearothermophilus (TLP-ste) and Bacillus thermoproteolyticus (thermolysine). Boiling-resistant and calcium independent or dependent metallo-endopeptidases can be applied in several industrial processes, for instance in the preparation of the artificial sweetener aspartame, but also in the leather industry, in breweries and in the production of protein hydrolysates.