TY  - JOUR
A1  - Zeng, Ting
A1  - Leimkühler, Silke
A1  - Wollenberger, Ulla
A1  - Fourmond, Vincent
T1  - Transient Catalytic Voltammetry of Sulfite Oxidase Reveals Rate Limiting Conformational Changes
T2  - Journal of the American Chemical Society
N2  - Sulfite oxidases are metalloenzymes that oxidize sulfite to sulfate at a molybdenum active site. In vertebrate sulfite oxidases, the electrons generated at the Mo center are transferred to an external electron acceptor via a heme domain, which can adopt two conformations: a “closed” conformation, suitable for internal electron transfer, and an “open” conformation suitable for intermolecular electron transfer. This conformational change is an integral part of the catalytic cycle. Sulfite oxidases have been wired to electrode surfaces, but their immobilization leads to a significant decrease in their catalytic activity, raising the question of the occurrence of the conformational change when the enzyme is on an electrode. We recorded and quantitatively modeled for the first time the transient response of the catalytic cycle of human sulfite oxidase immobilized on an electrode. We show that conformational changes still occur on the electrode, but at a lower rate than in solution, which is the reason for the decrease in activity of sulfite oxidases upon immobilization.
Y1  - 2017
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/46427
SN  - 0002-7863
VL  - 139
SP  - 11559
EP  - 11567
PB  - American Chemical Society
CY  - Washington
ER  -