Phthalyl amidase

The anomalous behaviour observed in attempted 1-deprotection of certain 4-heteroarylmethyl-l-(4-methoxyphenyl)-2-azetidinones by the action of CAN has been investigated further <961771 > and evidence obtained to support the mechanism proposed, which involves the intermediate 47 when the 4-substituent is the tetrazolylmethyl group as in 46 <96T10169>. Use of the novel enzyme, o-phthalyl amidase, as a deprotection agent for P-lactams has been developed <96MI875>. 

The phthalimido group has always been an attractive alternative to amine protection in chemical synthesis. Native phthalyl amidase was isolated from Xanthiobacter agilis and subsequently cloned and overexpressed in Streptomyces lividans. Phthalyl amidase selectively deprotects phthalimido groups under very mild conditions (30°C in 200 mM potassium phosphate buffer, pH 8.0) in a one-pot reaction to produce phthalic acid and the free amine. The enzyme has been shown to deprotect several primary amines of distinctly different structures [19]. 

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