The Isolation of O-Acetylated Fragments from the K Antigen of Escherichia coli 08: K 27(A) : H by the Action of Phage-Induced Enzymes from Klebsiella aerogenes.

Phage-induced fucosidases prepared from cell lysates of a Klebsiella aerogenes strain have been shown to hydrolyse the polysaccharide of Escherichia coli K27. The major hydrolysis product of one enzyme was identified as an acetylated tetrasaccharide containing equimolar amounts of galactose, glucose, glucuronic acid and fucose. The reducing terminus was characterised as fucose. A minor product of enzymic hydrolysis was the corresponding unacetylated tetrasaccharide. This oligosaccharide was also obtained from alkali-treated polysaccharide. Neither tetrasaccharide could be hydrolysed further with glycosidases. The product of hydrolysis with the second enzyme was probably an octasaccharide comprising two repeating units of the E. coli polysaccharide. It also contained equimolar amounts of the constituents and approximately 50% of the fucose was reduced with borohydride, From the results it is concluded that both enzymes require the sequence ....... α-glucuronosyl — 1 → 3 fucosyl-glucose for substrate activity. The presence of the O-acetyl groups was not essential for enzymic hydrolysis. [ABSTRACT FROM AUTHOR]