Structure and stability of glucoamylase II from Aspergillus niger: A circular dichroism study.

Shenoy, B. C. and Appu Rao, A. G. and Raghavendra Rao, M. R. (1984) Structure and stability of glucoamylase II from Aspergillus niger: A circular dichroism study. Journal of Biosciences, 6 (5). pp. 601-611.

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Abstract

Glucoamylase II (Ee 3.2.1.3) from Aspergillus niger bas 31%a-helix, 36% beta structure and rest aperiodic structure at pH 4·8 as analysed by the method of Provencher and Glockner (1981, Biochemistry, 20, 33). In the near ultra-violet circular dichroism spectrum the enzyme exhibits peaks at 304, 289, 2.'12 and 257 nm and troughs at 285, 277 and 265 nm respectively. The enzyme activity and structure showed greater stability at pH 4'8 than at pH 7'0, were highly sensitive 10 alkaline pH but less sensitive to acid pH values. The enzyme retained most of its catalytic activity and structure even on partial removal of carbohydrate moieties by periodale treatment bul was less stable al higher temperatures and storage at 30 degree centigrade. Reduction of the periodate treated enzyme did not reverse the loss of stability. Binding of the synthetic substrate, p-nitrophenyl-a·D-glucoside, perturbed the environment around aromatic amino acids and caused a decrease in the ordered structure.

Item Type:	Article
Uncontrolled Keywords:	Aspergillus niger; g1ucoamylase; circular dichroism; carbohydrate moieties
Subjects:	500 Natural Sciences and Mathematics > 07 Life Sciences > 03 Biochemistry & Molecular Biology > 05 Carbohydrate Biochemistry 500 Natural Sciences and Mathematics > 07 Life Sciences > 04 Microbiology > 04 Fungi
Divisions:	Dept. of Biochemistry
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	22 Jun 2016 08:19
Last Modified:	22 Jun 2016 08:19
URI:	http://ir.cftri.res.in/id/eprint/5535

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