A 27 year old man presents to the Accident and Emergency Department saying that he thinks he is having an allergic reaction to the fava beans he consumed for the first time in his life earlier in the day.   The physician suspects that the patient has glucose 6-phosphate dehydrogenase deficiency (G6PD) which was asymptomatic until the consumption of fava beans which triggered the favism observed.  Upon investigation, the patient also has hemolytic anaemia.

 Which of the following explanations best describe why hemolytic anaemia is observed in patients with G6PD?