2. It is known hemoglobinopathies, which arise due to mutations in one of histidines a-or beta - chains binding with the iron in the heme group These mutations stabilize the iron in Fe^3+ form.Some drugs (eg. sulfonamides) or chemicals (eg. anilin) also can cause methemoglobinemia . Suggest, how change the properties of Hb in these cases For this: 1) Describe the structure and function of Hb A as a transport protein. 2) Explain the role of iror ions in active centers of Hb for the binding of O_(2) 3) How many molecules of O_(2) can bind mutant Hb if mutation occurs in alpha - subunits? 4) Why can ascorbic acid be used to treat of such patients.

1) Hemoglobin A (HbA) is a tetrameric protein composed of two alpha (α) and two beta (β) subunits. Its primary function is to transport oxygen (O2) from the lungs to tissues and organs throughout the body. Each subunit contains a heme group with an iron ion (Fe2+) that can bind to O2.<br /><br />2) The iron ions in the active centers of Hb play a crucial role in the binding of O2. The Fe2+ ion in the heme group can reversibly bind to O2, allowing Hb to pick up and release O2 as needed. This binding is essential for the transport of O2 in the bloodstream.<br /><br />3) If a mutation occurs in the α subunits of Hb, it can affect the binding of O2. The number of O2 molecules that can bind to mutant Hb depends on the specific mutation and its impact on the structure and function of the α subunits. In general, mutations in the α subunits can lead to a reduced affinity for O2, resulting in decreased oxygen-carrying capacity.<br /><br />4) Ascorbic acid, also known as vitamin C, can be used to treat patients with hemoglobinopathies because it has antioxidant properties. Ascorbic acid can reduce the formation of methemoglobin, a form of hemoglobin that has a reduced affinity for O2. By converting methemoglobin back to its normal form, ascorbic acid helps improve the oxygen-carrying capacity of Hb.