[An abzyme to catalytize the deiodination of thyroxine].
OBJECTIVE
To mimic an important family of selenoenzymes in organism-thyroxine (T4) deiodinases and prepare a selenium-containing abzyme catalyzing deiodination of T4.


METHODS
A anti-T4 monoclonal antibody was generated by hybridoma methodology and converted into a selenium-containing abzyme by the method of chemical modification. The catalytic activity of the enzyme was measured by RIA method.


RESULTS
The abzyme displayed a marked activity of catalyzing deiodination of T4 and a higher specificity to the substrate T4 than that of natural enzyme, and the double reciprocal plots of the initial rates of T3 formation vs. T4 concentration yielded a family of parallel lines. The catalytic activity could be sensitively inhibited by 6-propyl-2-thiouracil (PTU), a competitive inhibitor for dithiothreitol (DTT).


CONCLUSIONS
An abzyme with the diodination activity was first prepared and the reaction mechanism of the enzyme was bisubstrate ping-pong one.
Lian
G W
GW
Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Chen
M
M
Liu
Z
Z
Ding
L
L
Zhao
D Q
DQ
Ni
J Z
JZ
D000818:Animals; D017151:Antibodies, Catalytic / Q000378:metabolism* / Q000494:pharmacology*; D000911:Antibodies, Monoclonal / Q000378:metabolism; D005260:Female; D007453:Iodide Peroxidase / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D012643:Selenium; D013974:Thyroxine / Q000378:metabolism*; D014284:Triiodothyronine / Q000096:biosynthesis
D017151:Antibodies, Catalytic; D000911:Antibodies, Monoclonal; D014284:Triiodothyronine; C481917:Se-4C5 abzyme; D007453:Iodide Peroxidase; D012643:Selenium; D013974:Thyroxine