scholarly journals Specificity and action pattern of heparanase Bp, a β-glucuronidase from Burkholderia pseudomallei

Glycobiology ◽  
2019 ◽  
Vol 29 (8) ◽  
pp. 572-581 ◽  
Author(s):  
Yanlei Yu ◽  
Asher Williams ◽  
Xing Zhang ◽  
Li Fu ◽  
Ke Xia ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Burkholderia Pseudomallei ◽  
Uronic Acid ◽  
Pathogenic Bacteria ◽  
Glucuronic Acid ◽  
Structural Determination ◽  
Action Pattern ◽  
Oligosaccharide Mapping ◽  
Size And Structure

AbstractThe specificity and action pattern of a β-glucuronidase derived from the pathogenic bacteria Burkholderia pseudomallei and expressed in Escherichia coli as a recombinant protein has been evaluated. While this enzyme shows activity on a number of glycosaminoglycans, our study has focused on its action on heparin, heparan sulfate and their biosynthetic intermediates as well as chemoenzymatically synthesized, structurally defined heparan sulfate oligosaccharides. These heparin/heparan sulfate (HP/HS) substrates examined varied in size and structure, but all contained an uronic acid (UA) residue β-(1→4) linked to a glucosamine residue. On the substrates tested, this enzyme (heparanase Bp) acted only on a glucuronic acid residue β-(1→4) linked to an N-acetylglucosamine, N-sulfoglucosamine or N-acetyl-6-O-sulfoglucosamine residue. A substrate was required to have a length of pentasaccharide or longer and heparanase Bp acted with a random endolytic action pattern on HP/HS. The specificity and glycohydrolase mechanism of action of heparanase Bp resembles mammalian heparanase and is complementary to the bacterial heparin lyases, which act through an eliminase mechanism on a glucosamine residue (1→4) linked to a UA residue, suggesting its utility as a tool for the structural determination of HP/HS as well as representing a possible model for the medically relevant mammalian heparanase. The utility heparanase Bp was demonstrated by the oligosaccharide mapping of heparin, which afforded resistant intact highly sulfated domains ranging from tetrasaccharide to >28-mer with a molecular weight >9000.

scholarly journals Reaction of unsaturated uronic acid residues with mercuric salts. Cleavage of the hyaluronic acid disaccharide 2-acetamido-2-deoxy-3-O-(β-d-gluco-4-enepyranosyluronic acid)-d-glucose

1987 ◽  
Vol 245 (3) ◽  
pp. 795-804 ◽  
Author(s):  
U Ludwigs ◽  
A Elgavish ◽  
J D Esko ◽  
E Meezan ◽  
L Rodén
Keyword(s):  
Hyaluronic Acid ◽  
Connective Tissue ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Reaction Products ◽  
Acid Moiety ◽  
Analytical Work ◽  
Almost All

Degradation of connective-tissue polysaccharides with bacterial or fungal eliminases and subsequent characterization of the reaction products are now part of standard methodology for the analysis of these compounds. However, the scope of preparative and analytical work based on the use of eliminases has been limited by the lack of procedures for specific removal of the unsaturated uronic acid residues generated in the eliminase reactions. In the present investigation, we have shown that these residues are cleaved by mercuric salts under mild conditions that are not likely to affect other structures in an oligo- or poly-saccharide molecule. Thus the disaccharide generated from hyaluronic acid by digestion with chondroitinase AC or ABC was cleaved into a keto acid and free N-acetylglucosamine within 10 min at room temperature upon exposure to 14 mM-mercuric acetate at pH 5. The reaction of the disaccharide with mercuric salts was used for ready determination of the distribution of radioactivity between the glucuronic acid and N-acetylglucosamine moieties in radioactive hyaluronic acid that had been synthesized by IMR-90 fibroblasts from 3H-labelled monosaccharides. When the precursor was [3H]galactose, over 95% of the incorporated radioactivity was found in the glucuronic acid moiety. In contrast, cells grown in the presence of [3H]glucosamine synthesized a polysaccharide in which almost all of the label was located in the N-acetylglucosamine units. It is apparent from these experiments that the reaction of unsaturated uronic acid residues with mercuric salts provides a new tool with potential for many applications in the study of the structure and metabolism of connective-tissue polysaccharides.

Structural Determination of Certain Novel ER Complexes

2004 ◽  
Author(s):  
Ya-Ling Wu ◽  
Geoffrey L. Greene
Keyword(s):  
Structural Determination

Phytochemical Constituents of Annona reticulata and their Cytotoxic Activity

2020 ◽  
Vol 17 (3) ◽  
pp. 206-210
Author(s):  
Ty Viet Pham ◽  
Thang Quoc Le ◽  
Anh Tuan Le ◽  
Hung Quoc Vo ◽  
Duc Viet Ho
Keyword(s):  
Cytotoxic Activity ◽  
Cell Lines ◽  
Structural Determination ◽  
Phytochemical Investigation ◽  
Ic50 Values ◽  
Phytochemical Constituents ◽  
First Time ◽  
Annona Reticulata

A phytochemical investigation of the leaves of Annona reticulata led to the isolation and structural determination of β-sitosterol (1), ent-pimara-8(14),15-dien-19-oic acid (2), ent-pimara- 8(14),15-dien-19-ol (3), quercetin (4), quercetin 3-O-α-L-arabinopyranoside (5), and a mixture of quercetin 3-O-β-D-galactopyranoside (6a) and quercetin 3-O-β-D-glucopyranoside (6b). Of these, compounds 2 and 3 were isolated from the genus Annona for the first time. Compound 3 showed strong cytotoxicity against SK-LU-1 and SW626 cell lines with IC50 values of 17.64 ± 1.07 and 19.79 ± 1.41 μg mL-1, respectively.

Binding of lead and copper(II) cations to hemicelluloses of rye bran

1986 ◽  
Vol 51 (10) ◽  
pp. 2250-2258 ◽  
Author(s):  
Rudolf Kohn ◽  
Zdena Hromádková ◽  
Anna Ebringerová
Keyword(s):  
Uronic Acid ◽  
Equilibrium Solution ◽  
Glucuronic Acid ◽  
The Other ◽  
Carboxyl Groups ◽  
Stoichiometric Ratio ◽  
Molar Ratios ◽  
Free Ions ◽  
Uronic Acid Content ◽  
The Relationship

Several fractions of acid hemicelluloses isolated from rye bran were characterized by molar ratios of saccharides (D-Xyl, L-Ara, D-Glc, D-Gal) and 4-O-methyl-D-glucuronic acid and protein content. Binding of Pb2+ and Cu2+ ions to these acid polysaccharides was considered according to function (M)b = f([M2+]f), expressing the relationship between the amount of metal (M)b bound to 1 g of the substance and the concentration of free ions [M2+]f in the equilibrium solution and according to the association degree β of these cations with carboxyl groups of uronic acid at a stoichiometric ratio of both components in the system under investigation. Acid hemicelluloses contained only a very small portion of uronic acid ((COOH) 0.05-0.18 mmol g-1); the model polysaccharide, 4-O-methyl-D-glucurono-D-xylan of beech, was substantially richer in uronic acid content ((COOH) 0.73 mmol g-1). Consequently, the amount of lead and copper bound to acid hemicelluloses is very small ((M)b 0.017-0.025 mmol g-1) at [M2+]f = 0.10 mmol l-1. On the other hand, much greater amount of cations ((M)f 0.09-0.10 mmol g-1) was bound to the glucuronoxylan. The association degree β was like with the majority of samples (β = 0.31-0.38). The amount of lead and copper(II) bound to acid hemicelluloses from rye bran is several times lower than that bound to dietary fiber isolated from vegetables (cabbage, carrot), rich in pectic substances.

Sign in / Sign up

Export Citation Format

Share Document