Dear Soumya,

Serine and glycine are the amino acids.

Before discussing the actual mechanism of photophosphorylation,let me discuss the first step of Calvin cycle:

RuBP combines with CO2and yields 2 molecules of 3-Phosphoglycerate (3-PGA)
in the presence of enzyme RuBisCO.

RuBisCO also act as ribulose bisphosphate oxygenase under low atmospheric concentration of CO2and increased concentration O2.

In presence of high concentration of O2,the oxygenase activity of enzyme Ribulose bisphosphate oxygenase perform the first reaction and rest by other enzymes:

Ribulose-1,5-bisphosphate ----> 2 Phosphoglycolic acid + Phosphoglyceric acid

2 Phosphoglycolic acid + H2O ----> Glycolic acid + Glyceric acid

Glycolic acid + O2-----> Glyoxylic acid +H2O2

Glyoxylic acid + Glutamic acid ---> Glycine +α-Keto glutaric acid

2 glycine + H2O + NAD+ ------> Serine + CO₂ + NH₃ + NADH


Hope the answer of the question!