<prompt> Which of the following statement characterize both Hemoglobin and Myoblogin -Non-helicalSubunits which are held together by hydrogen bondsBinds with 2 HemeHeme at hydrophobic pockets  <response>: Heme lies in the hydrophobic interior pocket of globin chain of hemoglobin and myoglobin.Polypeptide chain of myoglobin and all four polypeptide chains of hemoglobin have helical structure.Polypeptide subunits of hemoglobin are held together by hydrogen bonds, salt ionic bonds and Van der walls forces. Myoglobin has only one polypeptide chain, thus there is no question of bonding between subunits.However, this should not be confused that there is no bonds in myoglobin. Myoglobin has secondary and tertiary structure which are stabilized by non-covalent bonds. Polypeptide chain of myoglobin is compactly folded so that the non-polar hydrophobic amino acids lies in the interior forming hydrophobic bonds and polar hydrophilic amino acid on the exterior surface forming hydrogen and electrostatic ionic bonds. So, compact structure of myoglobin is stabilized by hydrogen and ionic bonds as well as by the hydrophobic interactions.Similarly, Each polypeptide chain of hemoglobin is stabilized by hydrophobic bonds in interior and hydrogen and ionic electrostatic bonds on exterior.Thus :-Stabilization of polypeptide chain itself of hemoglobin and myoglobin hydrogen bonds, electrostatic ionic bonds and hydrophobic bonds.Subunits 4 polypeptide chains of hemoglobin are held together by hydrogen bonds, electrostatic bonds and Van der walls forces.A hemoglobin molecule binds 4 molecules of O2 and a myoglobin molecule binds 1 molecule of O2Each hemoglobin molecule has 4 heme groups and myoglobin has one heme group. 