myoglobin /mī′ōglō″bin/ [Gk, mys + L, globus, ball] , a ferrous globin complex in muscle consisting of one heme molecule containing one iron molecule attached to a single globin chain. Myoglobin is responsible for the red color of muscle and for its ability to store oxygen. Normal blood levels of myoglobin are 0-85 ng/mL. Excessive myoglobin levels may result from burns, muscle-wasting diseases, acute myocardial infarction, or trauma.