Inhibition of Glycine Decarboxylation by Aminoacetonitrile and its Effect on Photosynthesis in Wheat

Abstract

Aminoacetonitrile was found to be a competitive inhibitor of glycine oxidation by isolated wheat leaf mitochondria (K₁ = 126 μM). The decarboxylation of glycine by wheat protoplasts was also inhibited by aminoacetonitrile. Concentrations of aminoacetonitrile up to 50 mM had no effect on the fixation of CO2 (at 0.3 mM or 10 mM bicarbonate) by isolated wheat chloroplasts. However, at the lower concentration of bicarbonate, the compound reduces the rate of photosynthesis in wheat protoplasts and glycine becomes the major photosynthetic product as carbon flow through the glycollate pathway is decreased.