Myeloperoxidase deficiency

Gene Information


HUGO name: MPO


  • Myeloperoxidase
  • Myeloperoxidase precursor


Reference sequences

Chromosomal location


Protein Information


Protein function:

Part of the host defense system of polymorphonuclear leukocytes. It is responsible for microbicidal activity against a wide range of organisms. In the stimulated PMN, MPO catalyzes the production of hypohalous acids, primarily hypochlorous acid in physiologic situations, and other toxic intermediates that greatly enhance PMN microbicidal activity.

Catalytic activity:

Cl(-) + h(2)o(2) = hocl + 2 h(2)o


Tetramer of two light chains and two heavy chains.


Binds 1 heme B (iron-protoporphyrin IX) group covalently and 1 calcium ion per heterodimer.

Structures (PDB)

1MHL Crystal Structure Of Human Myeloperoxidase Isoform C Crystallized In Space Group P2(1) At pH 5.5 and 20 Deg C
1CXP Cryogenic Crystal Structure Of Human Myeloperoxidase Isoform C
1D2V Crystal Structure Of Bromide-Bound Human Myeloperoxidase Isoform C At pH 5.5
1D5L Crystal Structure Of Cyanide-Bound Human Myeloperoxidase Isoform C At pH 5.5
1D7W Crystal Structure Of Human Myeloperoxidase Isoform C Complexed With Cyanide and Bromide At pH 4.0
1DNU Structural Analyses Of Human Myeloperoxidase-Thiocyanate Complex
1DNW Human Myeloperoxidase-Cyanide-Thiocyanate Complex


Other features

Signal peptide: 1-48

    Propeptide: 49-164

      Myeloperoxidase: 165-745

        89 kda myeloperoxidase: 49-745

          84 kda myeloperoxidase: 155-745

            Myeloperoxidase light chain: 165-278

              Myeloperoxidase heavy chain: 279-745

                Calcium-binding region: 262

                  Calcium-binding region: 334

                    Calcium-binding region Via carbonyl oxygen: 336

                      Calcium-binding region: 338

                        Calcium-binding region: 340

                          Protoheme ix (covalent) binding site: 260

                            Protoheme ix (covalent) binding site: 408

                              Protoheme ix (covalent) binding site: 409

                                Iron (protoheme ix axial ligand) binding site: 502

                                  Disulfide bond: 167-180

                                    Disulfide bond: 281-291

                                      Disulfide bond: 285-309

                                        Disulfide bond interchain: 319

                                          Disulfide bond: 387-398

                                            Disulfide bond: 606-663

                                              Disulfide bond: 704-730

                                                N-linked (glcnac...) glycosylation site: 355

                                                  N-linked (glcnac...) glycosylation site: 391

                                                    N-linked (glcnac...) glycosylation site: 483

                                                      Other related resourses:


                                                      Expression pattern for human

                                                      Tissue Expression (%) Clones
                                                      whole blood 75.26 23:2445
                                                      leukopheresis 10.53 6:4557
                                                      cord blood 6.19 6:7759
                                                      thymus, pooled 2.52 1:3169
                                                      rpe and choroid 1.51 2:10565
                                                      pool, liver+spleen 0.91 7:61327
                                                      bone marrow 0.81 2:19854
                                                      bone 0.64 1:12499
                                                      unclassified 0.62 4:51898
                                                      pool, lung+testis+B-cell 0.57 4:55714