What enzyme deficiency in RBC leads to hemolytic anemia due to oxidative stress? ​

In some cases, massive destruction of red blood cells caused death. This drug-induced hemolytic anemia was shown 30 years later to be caused by a deficiency of glucose 6-phosphate dehydrogenase, the enzyme catalyzing the first step in the oxidative branch of the pentose phosphate pathway.

in short terms, glucose 6-phosphate dehydrogenase

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.