1.21.3.1 isopenicillin-n synthase deficiency http://www.ncbi.nlm.nih.gov/htbin-post/Entrez/query?uid=1900348&form=6&db=m Expression of the penDE gene of Penicillium chrysogenum encoding isopenicillin N acyltransferase in Cephalosporium acremonium: production of benzylpenicillin by the transformants. unassigned -