Structure myeloperoxidase heme

Figure 9 Structure of myeloperoxidase (MPO) along with the heme environment as observed in the high-resoiution crystal stmcture. (This figure was generated from coordinates of ICXP deposited in the Protein Data Banlr)...

The opportunities for MCD spectroscopy in the visible region are far more extensive. The MCD of the visible absorption bands of porphyrins have been probed by MCD since the beginning of the field. The sensitivity of the MCD spectra to the environment of porphyrin derivatives, in solution as well as embedded in proteins, provides information on both electronic structure and physical conformation. As an example, Dawson and colleagues have used MCD to probe the identity of the heme-type prosthetic group of myeloperoxidase. Such capabilities combined with the seemingly infinite number of metalloproteins available in nature provide ample opportunities for the productive use of MCD. 

Myeloperoxidase is the principal heme protein of the mammalian neutrophil functioning in the phagocytic process through its capacity at acid pH to peroxidize chloride ions to hypochlorous acid. Investigations of the structure of myeloperoxidase from various species have shown it to be a two-heme protein with a molecular weight in the region 135,000-150,000 (Agner, 1958, 1970 Harrison and Schultz, 1976 Harrison et al, 1977). 

---