The heme prosthetic group is found in
Myoglobin is a monomeric protein that acts as a secondary oxygen transporter and binder in the muscle tissues. 
Furthermore, the tertiary feature of myoglobin resembles water-soluble globule protein characteristics. 
The diffusion and use of oxygen in the muscles are necessary for the bodily system processes such as respiration.
Myoglobin has 8 right-handed a-helices separately forming a polypeptide chain and each contains a single heme prosthetic group with a central bound iron atom.
Myoglobin
Cytochrome oxidase
Xanthine oxidase
Tyrosine