학술논문
Examination of the role of arginine-143 in the human copper and zinc superoxide dismutase by site-specific mutagenesis.
Document Type
Article
Author
Source
Journal of Biological Chemistry; August 1987, Vol. 262 Issue: 23 p11182-11187, 6p
Subject
Language
ISSN
00219258; 1083351X
Abstract
The active site arginine-143 of human Cu, Zn superoxide dismutase has been replaced by lysine or by isoleucine. The mutant proteins were expressed at high levels in yeast, purified, and the amino acid substitution explored through the use of group specific reagents. The specific activities of these enzymes, measured by the xanthine oxidase/cytochrome c method and by using dry weight determination to establish protein concentration, were: native enzyme, 6570 units/mg; Lys-substituted enzyme, 2840 units/mg, Ile-substituted enzyme, 708 units/mg. The active site arginine thus plays an important, but not an essential, role in the catalytic process.