Extracellular Enzyme From Myxobacter AL-1 That Exhibits Both β-1,4-Glucanase and Chitosanase Activities

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Abstract
An enzyme that has both β-1,4-glucanase and chitosanase activities is characterized. Evidence for homogeneity was obtained from electrophoresis and sedimentation velocity studies; only one N-terminal amino acid, valine, was found. Results of denaturation studies showed that β-1,4-glucanase and chitosanase activities decreased at equal rates. With carboxymethylcellulose as the substrate, a Km of 1.68 g of carboxymethylcellulose per liter of solution and a Vmax of 2.20 × 10−9 mol/min were found. With chitosan (the β-1,4-polymer of glucosamine) as the substrate, a Km of 0.30 g of chitosan per liter of solution and a Vmax of 0.75 × 10−9 mol/min were found. A pH optimum of 5.0 was found for β-1,4-glucanase activity, and pH optima of 5.0 and 6.8 were found for chitosanase activity. β-1,4-Glucanase activity had a temperature optimum of 38 C, and chitosanase activity had a temperature optimum of 70 C. Chitosan stabilized both enzyme activities at 70 C. Cellotriose was the smallest polymer capable of hydrolysis. Glucosamine was released by action of the enzyme upon cell wall preparations of several fungi. Images