RESUMO
Two different procedures were used to prepare pure samples of 'cytochrome b1' (column chromatography) and 'bacterioferritin' (immunoprecipitation) from Escherichia coli K-12 strain CA265. Both were crystallized, and X-ray-crystallographic data were compared with those from the bacterioferritin of E. coli strain W3300 used as a standard. We conclude that 'cytochrome b1' and 'bacterioferritin' are identical.
Assuntos
Proteínas de Bactérias , Grupo dos Citocromos b , Escherichia coli/análise , Ferritinas , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/isolamento & purificação , Precipitação Química , Cromatografia DEAE-Celulose , Grupo dos Citocromos b/imunologia , Grupo dos Citocromos b/isolamento & purificação , Difração de Raios XRESUMO
The production of the extracellular nuclease secreted by Staphylococcus aureus (Foggi strain) was studied in a fermentor in an attempt to improve yield and allow large-scale production of the enzyme. In shake flask cultures, 600 units/mL of the enzyme were produced routinely. However, only 450 units/mL of the enzyme at best were obtained in a small-scale fermentor (3 L). The supplementation of the air supply to the fermentor with carbon dioxide [20% (v/v)] increased levels of enzyme in the culture medium to 770 units/mL. Subsequently, this result was reproduced in larger fermentors (10 and 150 L). The possible mechanisms of the effect of carbon dioxide upon the growth of Staphylococcus aureus (Foggi) and the production of the enzyme are discussed.