Discuss the role of HMP shunt in relation to anti-oxidant activity in RBC.

Under the influence of different oxidants, hemoglobin in RBC may turn into methemoglobin, where ferrus iron of normal hemoglobin is converted to ferric form by losing one electron which is accepted by molecular oxygen to form superoxide. This superoxide causes lysis of RBC membrane and the methemoglobin that is produced loses oxygen carrying capacity. Therefore to save RBC, superoxide must be metabolized to H₂O and to maintain normal hemoglobin function methemoglobin must be converted back to normal hemoglobin. For these activities NADP2H provided by HMP shunt is needed.