Question

Deadly gas. Carbon monoxide is a colorless, odorless gas that binds to hemoglobin at an oxygen-binding site. Indeed, it binds 200 times as tightly as oxygen, accounting for its toxic nature. Even if only one of the four oxygen-binding sites on hemoglobin is occupied by carbon monoxide and the remaining three are bound to oxygen, oxygen is not released. Explain.

Answer 1

The binding of carbon monoxide (CO) with hemoglobin leads to an R state even in conditions that should produce the release of oxygen. In consequence, CO-hemoglobin binding shifts the oxygen dissociation curve to the left.

Step-by-step explanation:

Hemoglobin is a globular protein containing four heme groups that can bind to one oxygen each. This protein (hemoglobin) has two conformational states: the T-state, also known as deoxyhemoglobin (a tense state, where lacks O species), and the R-state, also known as oxyhemoglobin (a relaxed, fully oxygenated state). When carbon monoxide binds to hemoglobin, the protein can not release oxygen, shifting the oxygen dissociation curve -which expresses the percentage of oxygen saturation against the partial pressure of oxygen- to the left. Therefore, under CO-hemoglobin binding, the oxygen level in the tissues is reduced.