Enzyme‐catalysed Transformations of Compounds Containing the –CH2-AsO3H2 Group

Abstract

Enzymes that act on substrates R-O-POA recent observation is that HO-CH 2 -CHOH-CH 2 -CH 2 -AsO 3 H 2 is a good substrate for glycerol-3-phosphate dehydrogenase. The product is unstable and eliminates arsenite, sharing this ability with other 3-oxoalkylarsonates. Thus this enzyme-catalysed oxidation is a lethal synthesis, in view of the toxicity of arsenite. Another unusual biochemical reaction of an arsonic acid is seen in the ability of a bacterium to use arsonoacetate as its sole source of carbon and energy.In contrast with the elimination of arsenite by 3-oxoalylarsonic acids, 3-oxoalkylphosphonic acids, R-CO-CH 2 -CH 2 -PO 3 H 2 , are stable. 2-Oxoalkylphosphonic acids, R-CO-CH 2 -PO 3 H 2 , however, are moderately unstable to hydrolysis, yielding phosphate and R-CO-CH 3 . 2-Oxoalkylarsonic acids, R-CO-CH 2 -AsO 3 H 2 , decompose in the same way, but much more readily, yielding arsenate. © 1997

Speciation of Metals and Metalloids in Biological Systems

“…The similarities in the biochemical behaviours of phosphate-and arsenatecontaining substrate analogues have been reviewed (Dixon et al, 1997;Dixon, 1996). It has been shown that enzymes which act on R-O-PO 3 H 2 and R-CO-CH 2 -PO 3 H 2 can also catalyse reactions involving their arsenic analogues R-O-AsO 3 H 2 and R-CO-CH 2 -AsO 3 H 2 to give unstable products, which hydrolyse to give the more toxic arsenate species.…”

Counteracting arsenic toxicity: Curcumin to the rescue?

“…As can substitute phosphate in various biochemical reactions due to their identical structure and characteristics [64]. For instance, arsenate interacts with glucose and gluconate [65] to generate glucose-6-arsenate and 6-arsenogluconate, respectively.…”