Microbial enantioselective removal of the N-benzyloxycarbonyl amino protecting group

In order to deprotect N-carbobenzoxy-l-aminoacids (Cbz-AA) and related compounds, a series of microorganisms was selected from soil by enrichment cultures with Cbz-l-Glu as sole nitrogen source. A lyophilized whole-cell preparation of two Arthrobacter sp. strains grown on Cbz-Glu or Cbz-Gly exhibited a high cleavage activity. The conditions of hydrolysis have been optimized and a quantitative enantioselective deprotection of several Cbz-dl-amino acids was obtained, as well as the deprotection of N-carbamoylester derivatives of several synthetic amino compounds. The preparation of Cbz-d-allylglycine and l-allylglycine in high yield and high optical purity is described as an application of this method.

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► A whole-cell lyophilized powder of two Arthrobacter sp. strains is able to cleave the N-benzyloxycarbonyl group of most CbzAA.
► The enzyme is completely specific for l-amino derivatives.
► The enzyme is specific for protected derivatives having a free alpha carboxyl group, including non-natural aminoacids.
► Hydrolytic activity is highly stable, not dependent on metal divalent ions, but inhibited by Hg++ and Cu++ ions.