title: A pure enzyme catalyzing penicillin biosynthesis.
abstract: Isopenicillin N synthetase (cyclase) has been purified to homogeneity from Cephalosporium acremonium strain C-10. The enzyme has a molecular weight of 40,000 to 42,000 and yields a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme was purified in 10 percent yield by a combination of protamine sulfate and ammonium sulfate precipitations, gel filtration, and ion-exchange high-performance liquid chromatography. The purified enzyme can be stabilized with sucrose and stored at -20 degrees C for several weeks without any loss in activity.
mesh_terms: D000164:Acremonium / Q000201:enzymology; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D004798:Enzymes / Q000302:isolation & purification* / Q000378:metabolism; D010088:Oxidoreductases; D010406:Penicillins / Q000096:biosynthesis*
chemical_list: D004798:Enzymes; D010406:Penicillins; D010088:Oxidoreductases; C038370:isopenicillin N synthetase; C006414:penicillin N