Characterization of a mucoid Escherichia coli K12 strain, and chemical analysis of the exopolysaccharide

1972 ◽  
Vol 18 (7) ◽  
pp. 969-973 ◽  
Author(s):  
Stephen Shugar ◽  
Kenneth E. Sanderson
Keyword(s):  
Escherichia Coli ◽  
Chemical Analysis ◽  
Glucuronic Acid ◽  
Extracellular Polysaccharide ◽  
Spontaneous Mutant ◽  
Escherichia Coli K12 ◽  
Molar Ratios ◽  
Genetic Lesion ◽  
Long Form

A spontaneous mutant of Escherichia coli K12 C600 was isolated which is mucoid as a result of overproduction of an extracellular polysaccharide. This strain also forms filaments, is sensitive to ultraviolet irradiation, and has its genetic lesion closely linked to the lac gene. Its phenotype and map position are analogous to the lon mutation (long form). The exopolysaccharide contains fucose, glucose, galactose, and may contain glucuronic acid, but the molar ratios of these sugars differ from those previously reported.

Isolation and characterization of a new extracellular polysaccharide from a cellulose-negative strain of Acetobacter xylinum

1981 ◽  
Vol 27 (6) ◽  
pp. 599-603 ◽  
Author(s):  
Svein Valla ◽  
Johs. Kjosbakken
Keyword(s):  
Chemical Analysis ◽  
Culture Medium ◽  
Glucuronic Acid ◽  
Extracellular Polysaccharide ◽  
Acetobacter Xylinum ◽  
Molar Ratio ◽  
Acidic Polysaccharide ◽  
Isolation And Characterization ◽  
Structural Parts

An extracellular, acidic polysaccharide has been isolated from the culture medium of a spontaneous cellulose-negative strain of Acetobacter xylinum. Chemical analysis shows that the polymer is composed of glucose, mannose, rhamnose, and glucuronic acid in a molar ratio approximating 3:1:1:1. No evidence for the presence of cellobiose units as structural parts in the polysaccharide has been found.

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.

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