Involved in heme (porphyrin) scavenging. Binds hemoglobin and almost exclusively free-base protoporphyrin IX. Probably has a role as the central conduit of the isd heme uptake system, i.e. mediates the transfer of the iron-containing nutrient from IsdABH to the membrane translocation system IsdDEF. Hemin-free IsdC (apo-IsdC) acquires hemin from hemin-containing IsdA (holo-IsdA) probably through the activated holo-IsdA-apo-IsdC complex and due to the higher affinity of apo-IsdC for the cofactor. The reaction is reversible (By similarity). Monomer. Interacts with IsdA (By similarity). Anchored to the cell wall by sortase B (By similarity). Repressed by fur in the presence of iron. The NEAT domain binds Fe(3+) heme iron. Reduction of the high-spin Fe(3+) heme iron to high-spin Fe(2+) results in loss of the heme from the binding site of the protein due to the absence of a proximal histidine (By similarity). Belongs to the IsdC family.