Sulphate Lyases

An enzyme that hydrolyses dermatan sulphate, but neither chondroitin 4-sulphate nor chondroitin 6-sulphate, has been isolated from Flavobacterium heparinum grown in the presence of glycosaminoglycans. Chondroitin and dermatan sulphates and disaccharides obtained from them induced the synthesis of this enzyme, which was separated from a chondroitin sulphate lyase AC. The enzyme acted on dermatan sulphate to give an unsaturated, sulphated disaccharide and higher oligosaccharides. 

Dextranase NG is absorbed, without denaturation, onto a benzylated agarose derivative by hydrophobic interactions.  

The properties of a dextranase synthesized by an oral strain of Actinomyces israelii have been reported. Chemical analysis of the exo-dextranase ( go.w 4.35, p/4.17, mol. wt. 5.5 x 10 ) from Brevibacterium fuscum showed that it is a glycoprotein containing 429 amino-acid residues, neutral sugars (11 residues), and 2-amino-2-deoxyhexoses (3 residues), whereas the e/i fo-dextranase ( ao.w 4.37, p/4.9, mol. wt. 4.4 x 10 ) from Penicillium funiculasum contains 349 amino-acid residues (including cystine), neutral sugars (10 residues), and 2-amino-2-deoxyhexose (1 residue).  

Dextran induced the synthesis of a dextranase, which is attached to the outer membrane of the envelope, by an aerobic. Gram-negative bacterium closely related to Cytophaga Johnsonii. The use of proteolytic enzymes, snake venoms, and detergents in solubilizing a dextranase from C.johnsonii has been examined. Chymotrypsin was the only protease that efficiently solubilized the enzyme without destroying the enzymic activity. 

An extracellular e c/o-dextranase (mol. wt. 3.9 x 10, temperature optimum 55 °C, pH optimum 5.5, Km for dextran 1.1 x 10 moll ) from Fusarium moniliforme hydrolysed dextran to isomaltose. This enzyme was not inhibited by either iodoacetate or Hiedta and could be distinguished from commercial dextranases by electrophoresis. 

Values for Km and have been determined for the degradation of chondroitin 4- and 6-sulphates, chondroitin 4-sulphate proteoglycan, dermatan sulphate, and hyaluronic acid by a chondroitin sulphate lyase ABC obtained from Proteus vulgaris. The hydrolysis of chondroitin 4-sulphate by the enzyme was inhibited by hyaluronic acid, but not by keratan sulphate. The findings were discussed in connection with the use of chondroitin sulphate lyase ABC as a reagent for the degradation of tissue glycosaminoglycans. 

Arthrobacter aurescens secretes an enzyme that hydrolyses chondroitin sulphate. The enzyme crystallized after purification and exhibited the following properties pH optimum 6.0, temperature optimum 50 C, and pH stability 4.9—7.4 it was stable below 45 °C and hydrolysed chondroitin 4- and 6-sulphates, chondroitin, and hyaluronic acid (ratio of initial rates 1.0 1.1 1.95 3.2). The hydrolyses of chondroitin 4- and 6-sulphates furnished 2-acetamido-2-deoxy-3-0-(4-deoxy-a-L-t/irco-hex-4-enopyranosyluronic acid)-D-galactose 4- and 6-sulphates, respectively. Since the enzyme is inactive against dermatan sulphate, it is a chondroitin sulphate lyase AC. 

Enzymes that depolymerize chondroitin 4- and 6-sulphates have been found in mucosal scrapings from the stomachs of rats. Hydrolysis of chondroitin 4-sulphate yielded 2-acetamido-2-deoxy-3-0-(4-deoxy-a-L-/Areo-hex-4-enopyrano-syluronic acid)-D-galactose 4-sulphate. The stabilities of fractions enriched in the lyase(s) were investigated. 

A strain of Aspergillus ustus synthesizes a dextranase in amounts which are influenced by the quantity and nature of dextrans present during growth inhibition of the formation of this dextranase was also studied. The dextranase (mol. wt. 3.5 X 10 pH optimum 5.7 temperature optimum 50 °Q was purified to homogeneity by fractional precipitation, ion-exchange chromatography, and gel filtration it was stable at pH 5.5—8.5 and at temperatures 40 °C, but 50% of the activity was lost on heating at 50 °C for 15 min at pH 7.0. However, the enzyme was more stable to heat in the presence of Cr + and Al + ions, but was inhibited by Hg +, Ag+, and MnO - ions. 

Dextranase has been obtained from a strain of Brevibacterium fuscum by fractional precipitation, gel filtration, and ion-exchange chromatography. The enzyme (pH optimum 7.0—7.5) was stable over a wide pH range (5.0—11.0) and was activated by L-cysteine and H4edta, whereas it was inhibited by iodine, mercuric chloride, A-bromosuccinimide, and cupric sulphate. Since the hydrolysis of dextran by the enzyme afforded principally isomaltotriose, the enzyme appears to be a new ew-dextranase. 

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An improved method for the microdetermination of glycosaminoglycuronans after digestion with chondroitin sulphate lyase ABC and chondroitin sulphate lyase AC has been reported. However, it is based on the already reported... 

Glycosaminoglycans have been isolated from guinea-pig basophilic leukocytes after treatment with proteolytic enzymes. Further treatment with chondroitin lyase AC, chondroitin lyase ABC, and heparan sulphate lyase was used to identify chondroitin sulphate (55%), dermatan sulphate (30%), and heparan sulphate (15%). 

Cytochemical investigations have been used in the identification of heparan sulphate in glomerular basement membranes of rats. Specific anionic sites can be removed by treatment of perfused kidney cells with heparan sulphate-lyase or nitrous acid. Sialoglycoproteins and other glycosaminoglycans do not represent major components of these sites. The isolated membranes on digestion... 

The chondroitin sulphate lyase AC (mol. wt. 7.5—8.0 x 10" ) from Arthrobacter aurescens is a glycoprotein containing residues of D-mannose, D-glucose, 2-amino-2-deoxy-D-glucose, and D-glucuronic acid (molar proportions 3 5 4 2). The amounts of a-helix and -structure present in the protein chain were estimated to be 16 and 25 %, respectively, by o.r.d. and c.d. spectroscopy, etc. 

The arylsulphatase activity of rat spleen has been separated from the endogenous sulphamidase activity by isoelectric focusing. Mucosal scrapings from rats stomachs also contain arylsulphatase activity, although other sulphatases and chondroitin 4- and 6-sulphate lyases are also present. The stability of the arylsulphatase to storage was investigated. 

Heparin Lyases and Heparan Sulphate Lyases The isolation and partial characterization of a heparin lyase and two heparan sulphate lyases from Flavobacterium heparinum have been reported. ... 

Heparan sulphate lyase Heparan sulphate lyase 4.2.2.S 385... 

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