ABC and Chondroitin AC Lyases

24 Chondroitin ABC and Chondroitin AC Lyases An improved method described for the micro determination of glycosamino-glycans is based on digestion with chondroitin ABC and AC lyases. The method has, however, been published previously. The determination is based on the colour production of 4-deoxy-a-L-t/fr 4-enepyranosyluronic acid-containing disaccharides produced by the action of chondroitin ABC and AC lyases when the periodate-thiobarbituric acid method is applied to the a,j8-unsaturated disaccharides. Suitable conditions for the quantitative assay were described. 

To decide upon the action patterns of these enzymes, a new method for the calculation of the degree of multiple attack, based on a concept established by J. F. Rohyt and D. French Arch, Biochem. Biophys., 1967, 122, 8), was employed. It was shown that the degree of multiple attack was represented by 

The actions of the two chondroitinases AC have been compared via steady-state kinetics carried out at pH 6.0. The Arthrobacter enzyme was susceptible to salt activation/regression and bivalent metal ions such as Ca +, Co +, Mg +, and Ba + were more effective for activation than virulent ions such as Na+ and K+. Various kinetic parameters of the actions of the enzymes was determined and thermodynamic parameters were calculated. The results obtained suggested that the driving force of enzyme-substrate complex formation could be attributed to ionic interaction for Arthrobacter chondroitinase AC and to hydrophobic bonding for Flavobacterium chondroitinase AC. 

A bacterium previously shown to produce a novel type of dextranase (isomaltose-releasing dextranase) has been identified as Arthrobacter globiformis.  

An encfu-dextranase isolated from the culture fluid of Penicillium purpuro-genum did not act on isomaltose, hydrolyses isomaltotriose slowly, and hydrolysed isomaltotetraose rapidly with the formation of two molecules of isomaltose. The action of the enzyme upon dextrans with various degrees of branching and upon isomaltopentaitol was investigated. 

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