mineral homeostasis trait iron homeostasis trait Any measurable characteristic related to the state of equilibrium in the body with respect to this metallic element that normally occurs in the heme of hemoglobin, myoglobin, transferrin, ferritin, and iron-containing porphyrins; it is an essential component of enzymes such as catalase, peroxidase, and various cytochromes. Trait.ontology VT:0005637