Microbial
degradation is a highly efficient and reliable approach
for mitigating the contamination of sulfonylurea herbicides, such
as chlorimuron-ethyl, in soil and water. In this study, we aimed to
assess whether Kj-mhpC plays a pivotal role in the
degradation of chlorimuron-ethyl. Kj-mhpC enzyme
purified via prokaryotic expression exhibited the highest catalytic
activity for chlorimuron-ethyl at 35 °C and pH 7. Bioinformatic
analysis and three-dimensional homologous modeling of Kj-mhpC were conducted. Additionally, the presence of Mg+ and
Cu2+ ions partially inhibited but Pb2+ ions
completely inhibited the enzymatic activity of Kj-mhpC. LC/MS revealed that Kj-mhpC hydrolyzes the
ester bond of chlorimuron-ethyl, resulting in the formation of 2-(4-chloro-6-methoxypyrimidine-2-amidoformamidesulfonyl)
benzoic acid. Furthermore, the point mutation of serine at position
67 (Ser67) confirmed that it is the key amino acid at the active site
for degrading chlorimuron-ethyl. This study enhanced the understanding
of how chlorimuron-ethyl is degraded by microorganisms and provided
a reference for bioremediation of the environment polluted with chlorimuron-ethyl.