scholarly journals Isolation of pure anhydrotetracycline oxygenase from Streptomyces aureofaciens

1988 ◽  
Vol 253 (1) ◽  
pp. 263-267 ◽  
Author(s):  
I Vancurová ◽  
J Volc ◽  
M Flieger ◽  
J Neuzil ◽  
J Novotná ◽  
...  

Anhydrotetracycline oxygenase was purified to homogeneity from Streptomyces aureofaciens, a producer of tetracycline. The enzyme was purified 60-fold in a 40% yield by a two-step procedure using a combination of hydrophobic chromatography and ion-exchange h.p.l.c. Purified anhydrotetracycline oxygenase was homogeneous according to SDS/polyacrylamide-gel electrophoresis, isoelectric focusing, ion-exchange h.p.l.c. on a Mono Q HR 5/5 column and size-exclusion h.p.l.c. on a TSK G 3000 SW column. The enzyme consists of two subunits of Mr 57,500, as determined by SDS/polyacrylamide-gel electrophoresis.

1989 ◽  
Vol 56 (3) ◽  
pp. 391-397 ◽  
Author(s):  
K. F. Ng-Kwai-Hang ◽  
J. P. Pélissier

SummaryThe rapid isolation of major bovine caseins in gram quantities was investigated. Whole casein was precipitated from individual cow's milk by adjusting the pH to 4·6 and the precipitated casein was suspended in 4·5 M urea (pH 8·0) containing 0·02 M imidazole and 0·03 M β-mercaptoethanol, and bound on a QAE Zeta Prep 250 cartridge. Stepwise elution with the urea/imidazole β-mercaptoethanol buffer and varying amounts of NaCl gave five well resolved peaks, which were identified by polyacrylamide gel electrophoresis and fast protein liquid chromatography to be pure γ-casein, κ-casein. β-casein, β-casein and αs-casein, respectively. The ion exchange cartridge was regenerated by flushing with buffer containing 0·50 Μ-NaCl followed by equilibration with starting buffer before separation of next sample. The time required to run each sample including cartridge regeneration and equilibration was 4 hours.


1978 ◽  
Vol 173 (3) ◽  
pp. 759-765 ◽  
Author(s):  
J A Sharp ◽  
M R Edwards

CoA-transferase (succinyl-CoA-3-oxo acid CoA-transferase, EC 2.8.3.5) isolated from sheep kidney was purified to homogeneity. The purified enzyme has a specific activity of approx. 200 units/mg. A mol.wt. of 110000 was obtained by gel filtration on Sephadex G-200, and a lower mol.wt. of 102000 was determined by analytical ultracentrifugation. A sedimentation coefficient of 5.6S was also determined. A subunit mol.wt. of 56000 was obtained by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. Isoelectric focusing of sheep kidney extracts indicated the presence of a single band of CoA-transferase activity with pI9.0. However, isoelectric focusing of purified CoA-transferase showed the presence of two peaks of CoA-transferase activity with pI values of 8.7 and 8.4, suggesting the presence of proteolytic activity during purification. Evidence for sheep kidney CoA-transferase being a dimer of two identical subunits has been obtained from sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the amino acid composition, peptide ‘mapping’ and N-terminal analysis.


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