Purification and characterization of cytochrome c′ from Neisseria meningitidis

2005 ◽  
Vol 33 (1) ◽  
pp. 187-189 ◽  
Author(s):  
W.M. Huston ◽  
E.C. Lowe ◽  
C.S. Butler ◽  
J.W.B. Moir
Keyword(s):  
Escherichia Coli ◽  
Cytochrome C ◽  
Neisseria Meningitidis ◽  
Redox State ◽  
Photosynthetic Bacteria ◽  
Nitrosyl Complex ◽  
Purification And Characterization ◽  
Ph Dependent ◽  
Ph Range

Cytochrome c′, a c-type cytochrome with unique spectroscopic and magnetic properties, has been characterized in a variety of denitrifying and photosynthetic bacteria. Cytochrome c′ has a role in defence and/or removal of NO but the mechanism of action is not clear. To examine the function of cytochrome c′ from Neisseria meningitidis, the protein was purified after heterologous overexpression in Escherichia coli. The electronic spectra of the oxidized c′ demonstrated a pH-dependent transition (over the pH range of 6–10) typical of known c′-type cytochromes. Interestingly, the form in which NO is supplied determines the redox state of the resultant haem-nitrosyl complex. Fe(III)–NO complexes were formed when Fe(II) or Fe(III) cytochrome c′ was sparged with NO gas, whereas an Fe(II)–NO complex was generated when NO was supplied using DEA NONOate (diazeniumdiolate).

Purification and characterization of catalase HPII from Escherichia coli K12

1986 ◽  
Vol 64 (7) ◽  
pp. 638-646 ◽  
Author(s):  
Peter C. Loewen ◽  
Jacek Switala
Keyword(s):  
Escherichia Coli ◽  
Sodium Dodecyl ◽  
Purification And Characterization ◽  
Unusual Structure ◽  
Escherichia Coli K12 ◽  
Molecular Weights ◽  
Ph Range ◽  
Heme Cofactor ◽  
Native Molecular Weight

Catalase (hydroperoxidase II or HPII) of Escherichia coli K12 has been purified using a protocol that also allows the purification of the second catalase HPI in large amounts. The purified HPII was found to have equal amounts of two subunits with molecular weights of 90 000 and 92 000. Only a single 92 000 subunit was present in the immunoprecipitate created when HPII antiserum was added directly to a crude extract, suggesting that proteolysis was responsible for the smaller subunit. The apparent native molecular weight was determined to be 532 000, suggesting a hexamer structure for the enzyme, an unusual structure for a catalase. HPII was very stable, remaining maximally active over the pH range 4–11 and retaining activity even in a solution of 0.1% sodium dodecyl sulfate and 7 M urea. The heme cofactor associated with HPII was also unusual for a catalase, in resembling heme d (a2) both spectrally and in terms of solubility. On the basis of heme-associated iron, six heme groups were associated with each molecule of enzyme or one per subunit.

Expression, purification, and characterization of recombinant lumbrokinase PI239 in Escherichia coli

2010 ◽  
Vol 69 (2) ◽  
pp. 198-203 ◽  
Author(s):  
Zhe-rong Xu ◽  
Yun-mei Yang ◽  
Qi-feng Gui ◽  
Li-na Zhang ◽  
Lin Hu
Keyword(s):  
Escherichia Coli ◽  
Purification And Characterization
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