title: Exoenzymic activity of alpha-amylase immobilized on a phenol-formaldehyde resin.
abstract: Amylose and amylopectin from two starch sources were partially degraded by alpha-amylase immobilized on a phenol-formaldehyde resin. The degradation products were fractioned by gel-permeation chromatography and high-pressure, liquid chromatography. Two distinct fractions were obtained from tapioca amylose. One is a fragment having a molecular weight exceeding 200,000, and the other consists of oligosaccharides of low molecular weight with a degree of polymerization of 1-8. In contrast, treatment of tapioca amylose with soluble alpha-amylase produces a single fraction, nearly all of which has a molecular weight of less than 35,000, with only traces of small oligosaccharides detectable by high-pressure, liquid chromatography. Even wider differences were observed in degradation products from tapioca amylopectin. Similar activity-patterns were obtained with immobilized and soluble enzyme, using corn amylose and corn amylopectin as substrates. Immobilization of alpha-amylase on the resin apparently restricts the activity of the enzyme to the ends of the starch molecules, making it appear to be limited to exoenzymic activity.
mesh_terms: D000681:Amylases / Q000302:isolation & purification / Q000378:metabolism*; D001412:Bacillus subtilis / Q000201:enzymology; D005557:Formaldehyde; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism; D008970:Molecular Weight; D010636:Phenols; D011485:Protein Binding; D012116:Resins, Plant
chemical_list: D007527:Isoenzymes; D010636:Phenols; D012116:Resins, Plant; D005557:Formaldehyde; D000681:Amylases