title: Purification and properties of two extracellular beta-lactamases from Bacillus cereus 569-H.
abstract: 1. When Bacillus cereus 569/H was grown in a casamino acid (casein-hydrolysate) medium containing zinc sulphate rapid production of extracellular beta-lactamase II preceded that of beta-lactamase I. 2. beta-Lactamase I was separated from beta-lactamase II by fractional precipitation with ammonium sulphate. 3. beta-Lactamase I was purified by a process involving chromatography on Celite and DEAE-cellulose and beta-lactamase II by chromatography on DEAE-cellulose after denaturation of beta-lactamase I by heat. Both enzymes were obtained in crystalline form. 4. beta-Lactamase II prepared in this way appeared to have a higher molecular weight than beta-lactamase I and required Zn(2+) as a cofactor for both cephalosporinase and penicillinase activities.
mesh_terms: D001409:Bacillus cereus / Q000201:enzymology*; D002364:Caseins; D011232:Chemical Precipitation; D002845:Chromatography; D002850:Chromatography, Gel; D003460:Crystallization; D003470:Culture Media; D008970:Molecular Weight; D010405:Penicillinase / Q000302:isolation & purification*; D015032:Zinc
chemical_list: D002364:Caseins; D003470:Culture Media; D010405:Penicillinase; D015032:Zinc