Haem molecule minus iron (i.e. the organic ring-structure without the central metal ion), the accumulation of which, in red cells, indicates either iron deficiency or other situations of impaired iron incorporation into haem, e.g. that caused by lead poisoning. Its quantitation in red blood cells can be used as a functional index of iron status.
A compound found in hemoglobin, myoglobin, and the cytochromes.
An important natural compound that occurs as an iron complex in hemoglobin and other blood pigments. Elevated levels indicate porphyria (a congenital metabolic disease), lead poisoning, liver disease, or certain cancers.
A derivative of hemoglobin containing four pyrrole nuclei; C34H34N4O4 It occurs naturally and is formed from heme (ferriprotoporphyrin) by deletion of an atom of iron.