Why are we are protected to some extent against low level CO poisoning?
A)His F8 on Hb distorts the heme iron atom out of the heme plane and attracts O₂,but not CO.
B)Affinity of Hb for O₂ is much greater than for CO.
C)His E7 blocks perpendicular binding of CO to heme iron,allowing for better binding competition by O₂.
D)The competition of O₂ for heme is much greater than CO for heme.

Question

Quizplus · Accepted Answer

His E7 (histidine at the E7 position) in hemoglobin plays a role in blocking the perpendicular binding of carbon monoxide (CO) to the heme iron, which allows oxygen (O₂) to compete more effectively for binding sites on hemoglobin. This structural feature helps in protecting against low-level CO poisoning by reducing the affinity of hemoglobin for CO compared to O₂, thus allowing oxygen to be more effectively transported in the presence of CO.

Why Are We Are Protected to Some Extent Against Low