scholarly journals Biosynthesis of dermatan sulphate. Defructosylated Escherichia coli K4 capsular polysaccharide as a substrate for the d-glucuronyl C-5 epimerase, and an indication of a two-base reaction mechanism

1996 ◽  
Vol 313 (2) ◽  
pp. 589-596 ◽  
Author(s):  
Helgi H. HANNESSON ◽  
Åsa HAGNER-McWHIRTER ◽  
Kerstin TIEDEMANN ◽  
Ulf LINDAHL ◽  
Anders MALMSTRÖM
Keyword(s):  
Escherichia Coli ◽  
Reaction Mechanism ◽  
Acid Hydrolysis ◽  
Capsular Polysaccharide ◽  
Glucuronic Acid ◽  
Microsomal Enzyme ◽  
Dermatan Sulphate ◽  
Mild Acid Hydrolysis ◽  
Mild Acid ◽  
Escherichia Coli K4

The capsular polysaccharide from Escherichia coli K4 consists of a chondroitin {[GlcA(β1→3)GalNAc(β1→4)]n} backbone, to which β-fructofuranose units are linked to C-3 of D-glucuronic acid (GlcA) residues. Removal of the fructose units by mild acid hydrolysis provided a substrate for the GlcA C-5 epimerase, which is involved in the generation of L-iduronic acid (IdoA) units during dermatan sulphate biosynthesis. Incubation of this substrate with solubilized fibroblast microsomal enzyme in the presence of 3H2O resulted in the incorporation of tritium at C-5 of hexuronyl units. A Km of 67×10-6 M hexuronic acid (equivalent to disaccharide units) was determined, which is similar to that (80×10-6 M) obtained for dermatan (desulphated dermatan sulphate). Vmax. was about 4 times higher with dermatan than with the K4 substrate. A defructosylated K4 polysaccharide isolated after incubation of bacteria with D-[5-3H]glucose released 3H2O on reaction with the epimerase, and thus could be used to assay the enzyme. Incubation of a K4 substrate with solubilized microsomal epimerase for 6 h in the presence of 3H2O resulted in the formation of about 5% IdoA and approximately equal amounts of 3H in GlcA and IdoA. A corresponding incubation of dermatan yielded approx. 22% GlcA, which contained virtually all the 3H label. These results are tentatively explained in terms of a two-base reaction mechanism, involving a monoprotic L-ido-specific base and a polyprotic D-gluco-specific base. Most of the IdoA residues generated by the enzyme occurred singly, although some formation of two or three consecutive IdoA-containing disaccharide units was observed.

THE STRUCTURAL ANALYSIS OF SOME ACIDIC XYLANS BY PERIODATE OXIDATION

1962 ◽  
Vol 40 (2) ◽  
pp. 348-352 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Acid Hydrolysis ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Small Degree ◽  
Degree Of Polymerization ◽  
Borohydride Reduction ◽  
Mild Acid Hydrolysis ◽  
Degree Of Branching ◽  
Hydrolysis Of ◽  
Mild Acid

By determining the amount of formaldehyde produced on periodate oxidation of borohydride-reduced apple- and cherry-wood xylans the degree of polymerization was shown to be 155 and 100 respectively. Acid hydrolysis of the polyols obtained by periodate oxidation and borohydride reduction gave ethylene glycol in amounts indicating that these xylans have a small degree of branching. Mild acid hydrolysis of the polyols demonstrated that in these xylans D-glucuronic acid as well as 4-O-methyl-D-glucuronic acid was present and that some of the former occupied non-terminal positions.

EFFECT OF ACID HYDROLYZATES OF AGAR ON THE GROWTH OF ESCHERICHIA COLI

1959 ◽  
Vol 5 (6) ◽  
pp. 589-593 ◽  
Author(s):  
W. Yaphe
Keyword(s):  
Escherichia Coli ◽  
Acid Hydrolysis ◽  
Degradation Product ◽  
Inhibitory Effect ◽  
Degree Of Hydrolysis ◽  
Mild Acid Hydrolysis ◽  
Heat Labile ◽  
Hydrolysis Of ◽  
Different Levels ◽  
Mild Acid

Studies were carried out to determine the effect of the products of acid hydrolysis of agar on the growth of Escherichia coli. The inhibitory effect was associated with the degree of hydrolysis of the agar. This inhibition has been obtained at two very different levels of concentration. When the hydrolysis was complete, the inhibitory pattern was similar to that of 5-hydroxymethyl-2-furaldehyde. Under conditions of mild acid hydrolysis, the inhibitory effect was caused by a heat-labile degradation product of 3,6-anhydro-L-galactose.

FURTHER STUDIES ON THE ANTIGENS OF ESCHERICHIA COLI O26:B6

1966 ◽  
Vol 12 (2) ◽  
pp. 249-254
Author(s):  
Joseph E. McDade ◽  
W. Robert Bailey
Keyword(s):  
Escherichia Coli ◽  
Acid Hydrolysis ◽  
Molecular Complex ◽  
Cell Suspensions ◽  
Soluble Antigen ◽  
Mild Acid Hydrolysis ◽  
Hydrolysis Of ◽  
Mild Acid

The effect of heat on the O and B antigens of Escherichia coli serotype O26:B6 was studied. Aliquots of cell suspensions containing 1.5 × 1010 cells/ml were heated at 55, 65, 75, 85, and 100 °C, respectively, for 1 hour. The heated cells were centrifuged and the precipitinogen titer determined using O and OB antisera. The supernatants from cell suspensions heated at the higher temperatures contained proportionately more of the soluble antigen than those heated at the lower temperatures.Gel diffusion tests of the supernatants showed that both O and B antigens were released when cells were heated. Mild acid hydrolysis of a supernatant increased the B reactivity of that supernatant and slightly enhanced the O reaction. It was concluded from this study that the O and B antigens exist as a molecular complex; heating releases the B component from the complex and causes the increased agglutination with O antiserum.

Amino acid sequence of cyanogen bromide fragment CB5 of human hemopexin

1989 ◽  
Vol 54 (3) ◽  
pp. 803-810 ◽  
Author(s):  
Ivan Kluh ◽  
Ladislav Morávek ◽  
Manfred Pavlík
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Acid Hydrolysis ◽  
Cyanogen Bromide ◽  
Polypeptide Chain ◽  
Amino Acid Residues ◽  
Mild Acid Hydrolysis ◽  
Methionine Residue ◽  
Cyanogen Bromide Fragment ◽  
Mild Acid

Cyanogen bromide fragment CB5 represents the region of the polypeptide chain of hemopexin between the fourth and fifth methionine residue (residues 232-352). It contains 120 amino acid residues in the following sequence: Arg-Cys-Ser-Pro-His-Leu-Val-Leu-Ser-Ala-Leu-Thr-Ser-Asp-Asn-His-Gly-Ala-Thr-Tyr-Ala-Phe-Ser-Gly-Thr-His-Tyr-Trp-Arg-Leu-Asp-Thr-Ser-Arg-Asp-Gly-Trp-His-Ser-Trp-Pro-Ile-Ala-His-Gln-Trp-Pro-Gln-Gly-Pro-Ser-Ala-Val-Asp-Ala-Ala-Phe-Ser-Trp-Glu-Glu-Lys-Leu-Tyr-Leu-Val-Gln-Gly-Thr-Gln-Val-Tyr-Val-Phe-Leu-Thr-Lys-Gly-Gly-Tyr-Thr-Leu-Val-Ser-Gly-Tyr-Pro-Lys-Arg-Leu-Glu-Lys-Glu-Val-Gly-Thr-Pro-His-Gly-Ile-Ile-Leu-Asp-Ser-Val-Asp-Ala-Ala-Phe-Ile-Cys-Pro-Gly-Ser-Ser-Arg-Leu-His-Ile-Met. The sequence was derived from the data on peptides prepared by cleavage of fragment CB5 by mild acid hydrolysis, by trypsin and chymotrypsin.

scholarly journals Presence of 3-O-methyl-l-xylose in the lipopolysaccharide of Pseudomonas maltophilia N.C.T.C. 10257

1977 ◽  
Vol 163 (1) ◽  
pp. 173-175 ◽  
Author(s):  
F Brown ◽  
D J Neal ◽  
S G Wilkinson
Keyword(s):  
Acid Hydrolysis ◽  
Mild Acid Hydrolysis ◽  
Whole Cells ◽  
Pseudomonas Maltophilia ◽  
Mild Acid

3-O-Methyl-L-xylose was isolated from whole cells of Pseudomonas maltophilia N.C.T.C. 10257. The sugar is a component of lipopolysaccharide from which a polysaccharide also containing L-rhamnose and L-xylose was released by mild acid hydrolysis. 3-O-Methyl-L-xylose was absent from five other strains of Ps. maltophilia and one strain of Pseudomonas geniculata.

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