Photorespiratory reactions. Phosphoglycolate is formed as a product of the oxygenase reaction in chloroplasts. After dephosphorylation, glycolate is transported into peroxisomes where it is converted into glyoxylate and then glycine. In mitochondria, two glycines are converted into serine, after losing a carbon as CO₂ and ammonium ion. The serine is converted back into 3-phosphoglycerate and the ammonium ion is salvaged in chloroplasts.