Quinone-induced inhibition of urease: Elucidation of its mechanisms by probing thiol groups of the enzyme

A comparison of the effects of 1,4-naphthoquinone and 2-hydroxy-1,4-naphthoquinone (lawsone) on indole-3-acetic acid (IAA)-induced growth of maize coleoptile cells

“…The first is their ability to undergo a nucleophilic attack and the second is the capacity of quinone to produce reactive oxygen species (ROS) via redox cycling (see also "Introduction"). It should also be added that some naphthoquinones such as NQ or 2-methyl-1,4-NQ undergo both redox cycling and nucleophilic substitution reactions in cell systems (Gant et al 1988;Zaborska et al 2007). In turn, in accordance with the "acid growth hypothesis" of auxin action, IAA-induced growth is predominantly regulated by PM H + -ATPase, which similar to other ATPases, is sensitive to sulfhydryl reagents (Elzenga et al 1989;Hager and Lanz 1989).…”

Kinetics of jack bean urease inhibition by 2,3-dichloro-1,4-naphthoquinone. Elucidation of the mechanism: redox cycling and sulfhydryl arylation

“…This study is a continuation of our previous research on inhibitory influence of quinones on urease [15,16,23,24]. The examined quinones represented two types of inhibition kinetics.…”

“…The multisubstitution was observed for the urease inhibition by TCpBQ. The investigations showed that one TCpBQ molecule reacts with 2.3 ± 0.2 thiol groups [15]. This interaction causes strong conformational changes in enzyme molecule enclosing subunits.…”

“…One of the approaches meant to counteract this negative effect is the use of urease inhibitors in combination with urea fertilizers. Among a variety of substances studied as urease inhibitors are quinones and their derivatives [12][13][14][15][16]. This group of chemicals has been shown to be cytotoxic, therefore it has been utilised as anticancer, antibacterial or antimalarial drugs and fungicides [17,18].…”

“…In contrast to mentioned derivatives, 1,4-naphthoquinone is a time and concentration dependent inactivator of urease. The inactivation followed two mechanisms: arylation and oxidation of urease thiol residues provoked by quinone-catalyzed redox cycling [15,16].…”