title: Preparation and characterization of a dextran-amylase conjugate.
abstract: Bacillus amyloliquefaciens alpha-amylase was attached to dextran after activation of the polysaccharide by using a modification of the cyanogen bromide method. The soluble dextran-amylase conjugate was purified by molecular-sieve chromatography. The conjugated enzyme has greater stability than the unmodified enzyme at low pH values, during heat treatment, and on removal of calcium ions with a chelating agent. Attachment of dextran to alpha-amylase did not alter the Michaelis constant of the enzyme acting on starch. The polysaccharide-enzyme conjugate probably consists of a cross-linked aggregate of many dextran and many enzyme molecules, in which a proportion of the enzyme molecules, although not inactivated, are unable to express their activity, except after dextranase treatment.
mesh_terms: D000681:Amylases / Q000302:isolation & purification / Q000378:metabolism*; D001407:Bacillus / Q000201:enzymology; D003911:Dextrans; D004355:Drug Stability; D007700:Kinetics; D011485:Protein Binding; D012995:Solubility
chemical_list: D003911:Dextrans; D000681:Amylases