DCMU inhibits the electron transfer system in thylakoid membranes by targeting photosystem II (PSII). Specifically, it binds to the QB site of the D1 protein in PSII, preventing the transfer of electrons to plastoquinone. This leads to photoinhibition and blocks the flow of electrons from water to plastoquinone in the light reactions of photosynthesis.

DCMU Interferes with Pastoquinone-Protein Interactions Blocking Reduction of Pastoquinone and Subsequent Redox Reactions.

DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea) inhibits electron transport in chloroplasts by blocking the plastoquinone binding site in photosystem II. This prevents the reduction of plastoquinone and disrupts the flow of electrons in the photosynthetic electron transport chain. As a result, the light-dependent reactions of photosynthesis are impaired, leading to decreased ATP and NADPH production. Consequently, this inhibition affects overall photosynthetic efficiency and plant growth.