Debranching Enzymes of Potato Tubers (Solanum tuberosum L.)

摘要: A pullulanase (R-enzyme) was purified from potato tubers by fractional precipitation at pH 5, 20% ethanol precipitation, 40% saturated (NH4)4SO4 ion exchange chromatography on Whatman DE 32 and finally affinity Sepharose 6B-αCD. The final preparation having a specific activity of 11.4 U/mg obtained with yield 35.6%. enzyme separated gel filtration Sephadex G-150 into 2 forms, the apparent molecular weight which were calculated to be 220, 000 87, 000. Two forms converted spontaneously each other. hydrolyzed pullulan most rapidly, β-LDs more rapidly than their original polysaccharidesbut could not act oyster glycogen. It released maltosyl maltotriosyl residues poly-and oligosaccharides approximately same rate. All these catalytic properties are characteristic cereal pullulanases close those Aerobacter aerogenes (Klebsiella pneumoniae) pullulanase. isoamylase in previous paper hydrolyze all but instead glycogen quite well. favoured polysaccharides longer branch chains maltose stubs. Maltosyl stubs debranched much slowly this enzyme. identical Pseudomonas isoamylase. Data presented indicated clearly that have an