2.3.1.164 expressed in Escherichia coli JM109 2.3.1.164 expression in Escherichia coli 2.3.1.164 gene penDE 2.3.1.164 gene penDE, lack of correlation between the protein and transcript levels of the IAT enzyme, quantitative real-time PCR expression analysis and gene copy number determination, overexpression of penDE in Penicillium chrysogenum strains DS47274, DS47273, and DS17690, introduction of penDE gene without introns into these strains in a random manner, via the nonhomologous end-joining pathway. Cooverexpression of penDE with gene phl, encoding the phenylacetic acid CoA ligase leading to production of phenoxyacetyl-CoA and penicillin V 2.3.1.164 overexpression in Escherichia coli, not self-processed even when treated with Aspergillus nidulans crude extract 2.3.1.164 pPenIAT and pPenIATC103S are used to express the penDE gene in Penicillium chrysogenum, pPBCalphabeta, pDEC103S and palphabeta-DEC103S are used for expression in Escherichia coli 2.3.1.164 the intronless gene is expressed in Escherichia coli and self-processed efficiently into its alpha and beta subunits