Enzymic hydrolysis of the potassium chloride soluble fraction of carrageenan: properties of "λ-carrageenases" from Pseudomonas carrageenovora

Abstract

An enzyme complex which hydrolyzed the KCl soluble carrageenan extracted from the red alga Chondrus crispus has been isolated from the cell-free medium of a culture of Pseudomonas carrageenovora grown on this polysaccharide. Three hydrolases could be separated. Fraction I, which caused a rapid decrease in the specific viscosity of the polysaccharide preparation with only minimal release of reducing sugar, could be distinguished from fraction II chromatographically on Sephadex G-100 and electrophoretically on agarose gel. Fraction IIa caused release of reducing sugar at pH 6.2, which activity was depressed at pH 7.5. Fraction IIb exhibited viscometric activity only at both pH 6.2 and pH 7.5. Fraction IIa had a sharp pH optimum at pH 6.2 and a temperature optimum at 28°. All hydrolases were inactivated by freezing, by dialysis against distilled water, by heating at 35° for 30 min, and by Hg2+ and 0.0001 mM EDTA. When fraction II (a and b) isolated after chromatographic resolution on Sephadex G-100 was incubated at pH 6.2 with KCl soluble carrageenan from C. crispus, products which had Rgal values of 0.74 and 0.17 were detected, were sulfated, and contained no 3,6-anhydrogalactose.