Purification and characterization of a thermostable glucoamylase from the thermophilic fungus Thermomyces lanuginosus.

Rao, V Basaveswara and Sastri, NVS and Rao, PV Subba (1981) Purification and characterization of a thermostable glucoamylase from the thermophilic fungus Thermomyces lanuginosus. In: Biochemical Journal, 193 (2). 379-387..

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Abstract

Glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) was purified from the culture filtrates of the thermophilic fungus Thermomyces lanuginosus and was established to be homogeneous by a number of criteria. The enzyme was a glycoprotein with an average molecular weight of about 57 000 and a carbohydrate content of 10-12%. The enzyme hydrolysed successive glucose residues from the non-reducing ends of the starch molecule. It did not exhibit any glucosyltransferase activity. The enzyme appeared to hydrolyse maltotriose by the multi-chain mechanism. The enzyme was unable to hydrolyse 1,6-alpha-D-glucosidic linkages of isomaltose and dextran. It was optimally active at 70 degrees C. The enzyme exhibited increase in the Vmax. and decreased in Km values with increasing chain length of the substrate molecule. The enzyme was inhibited by the substrate analogue D-glucono-delta-lactone in a non-competitive manner. The enzyme inhibited remarkable resistance towards chemical and thermal denaturation.

Item Type:	Journal Article
Publication:	Biochemical Journal
Publisher:	Portland Press
Additional Information:	Copyright of this article belongs to Portland Press.
Department/Centre:	Division of Mechanical Sciences > Chemical Engineering
Date Deposited:	02 Jan 2010 08:54
Last Modified:	19 Sep 2010 05:47
URI:	http://eprints.iisc.ac.in/id/eprint/23891

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