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Isolation and characterization of N-acetyldehydroleucine acylase, a new enzyme from Zoogloea ramigera
Ist Teil von
Journal of fermentation and bioengineering, 1992-01, Vol.73 (2), p.99-107
Ort / Verlag
Osaka: Elsevier B.V
Erscheinungsjahr
1992
Link zum Volltext
Quelle
Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)
Beschreibungen/Notizen
A new acylase deacetylating various N-acetyl-2,3-didehydroamino acids was found in Zoogloea ramigera ABI1 (DSM 4306). The strain was selected from among 250 organisms obtained by enrichment culture with N-acetyldidehydroleucine, -valine or -isoleucine as sole sources of carbon and nitrogen. Enzyme production was improved from 15 U/l in shake flasks to 400 U/l by an optimized two stage fermentation process. The acylase was purified about 300 fold to an overall yield of 28% and a specific activity towards N-acetyldehydroleucine of 74–109 U/mg. The acylase has a molecular weight of 60000 dalton and consists of a single polypeptide chain, the pH-optimum of the reaction is in the range 7–9, while optimal stability was observed between pH 9 and 10.5 at temperatures up to 50°C. In a coupled reaction with L-leucine dehydrogenase and formate dehydrogenase the enzyme could be successfully employed for batch and continuous production of L-leucine with at least a 90% conversion yield.