Our knowledge on the release of copper from Cu-thionein in biological systems is limited. Other than oxidative cleavage or direct transfer, the possibility of an alkylation mechanism seemed attractive. Iodoacetamide and methyl methanesulphonate were successfully employed to alkylate the Cu-thiolate sulphur atom of homogeneous Cu(I)-thionein from yeast. The alkylation caused a weakening of the Cu-S bonding, which led to the release of copper. After equilibrium dialysis a proportion of the released copper was found in the dialysis buffer. When iodoacetamide was used carboxymethylcysteine was detected in the protein hydrolysate. A 10-fold molar excess over cysteine was sufficient for complete alkylation, which could be conveniently monitored by c.d. at 328 and 359 nm. The reaction proceeded under both aerobic and anaerobic conditions. E.p.r. measurements of Cu2+ revealed unequivocally the complete cleavage of the Cu-thiolate bonding in less than 5 h. It is possible that this mode of copper release might be of relevance to the molecular transport of this biochemically important transition metal.
Skip Nav Destination
Article navigation
June 1988
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
June 01 1988
Release of copper from yeast copper-thionein after S-alkylation of copper-thiolate clusters
K Felix;
K Felix
Anorganische Biochemie, Physiologisch-chemisches Institut, der Universität Tübingen, Hoppe-Seyler-Strasse 1, D-7400 Tübingen, Federal Republic of Germany
Search for other works by this author on:
U Weser
U Weser
Anorganische Biochemie, Physiologisch-chemisches Institut, der Universität Tübingen, Hoppe-Seyler-Strasse 1, D-7400 Tübingen, Federal Republic of Germany
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1988 London: The Biochemical Society
1988
Biochem J (1988) 252 (2): 577–581.
Citation
K Felix, U Weser; Release of copper from yeast copper-thionein after S-alkylation of copper-thiolate clusters. Biochem J 1 June 1988; 252 (2): 577–581. doi: https://doi.org/10.1042/bj2520577
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.