1-arseno-3-phosphoglycerate

1-Arseno-3-phosphoglycerate is a compound produced by the enzyme glyceraldehyde 3-phosphate dehydrogenase from glyceraldehyde 3-phosphate and arsenate in the glycolysis pathway. The compound is unstable and hydrolyzes spontaneously to 3-phosphoglycerate, bypassing the energy producing step of glycolysis.

...
Wikipedia