(1) An iron porphyrin, called heme , is the portion of hemoglobin that carries oxygen from the lungs to our body's cells.

(2) This turnover releases significant amounts of the iron-free portion of heme , porphyrin, which is subsequently degraded.

(3) The majority of photosensitizers are derivatives of hematoporphyrin, a synthetic porphyrin synthesized from heme .

(4) The harvested cell pellet was red, which suggested that the prosthetic group heme was synthesized by the bacterium.

(5) The active site or prosthetic group of all the cytochromes is an iron containing porphyrin, or heme .