Which of the following statements is FALSE? Which of the following statements is FALSE? Hemoglobin is a tetramer, each of which binds a heme group. In both hemoglobin and myoglobin, iron is chelated by a tetrapyrole ring system. The iron in both hemoglobin and myoglobin has two coordination sites that bind to oxygen. Myoglobin is a single polypeptide chain folded about a heme prosthetic group.

The false statement is The iron in both the hemoglobin and myoglobin has two coordination sites that bind to oxygen.

Explanation:

Hemoglobin is an oligomeric, allosteric, conjugated protein with 4 polypeptide chains joined by non covalent bonds that contain heme prosthetic group. It is an iron containing porphyrin derivative present in all vertebrate.

The tetramers of hemoglobin consists of numerous combinations of seven polypeptide chains and each of which is encoded by separate genes.

Myoglobin is a globular protein that consists of single polypeptide chain of 153 amino acid residue and a single heme group.

Globin of Mb binds with single heme group by forming co ordinate bond. The heterocyclic ring system of heme is a porphyrin derivative. It is made up of 4 pyrrole ring and 4 pyrroles are linked by methine bridges to form a tetrapyrolle ring.

The Fe atom is present either in Fe²⁺ state or Fe³⁺ oxidation state in the center of protoporphyrin IX ring. The iron atom has 6 co ordination bond, 4 in the plane of flat porphyrin ring and two perpendicular to it.