Subunit structures of three human myeloperoxidases.
The heavy and the light subunits of human myeloperoxidase (donor: H2O2 oxidoreductase [EC 1.11.1.7]) I, II, and III were isolated from the reduced and S-carboxymethylated enzymes. These three enzymes have the same terminal amino acid sequences and similar chemical compositions in both subunits. The NH2-terminal sequences of the heavy and light subunits were determined to be Val-Asn-Cys-Glu-Thr- and Thr-Cys-Pro-Glu-Gln-, respectively; a heterogeneity was observed in the NH2-termini of the latter subunits for the three enzymes. As for COOH-termini, the sequences -(Asn, 2 Leu, Ala, Ser, Trp)-Arg-Glu-Ala and -Ala-Arg were obtained for the heavy and the light subunits, respectively. The heavy subunits contained 8-10 mol/mol of glucosamine. On the basis of these results and the amino acid sequence deduced from cDNA clones, the heavy subunits probably correspond to amino acids 279-744 and the light subunits to amino acids (164-167)-272. For the heavy subunits, Ser-745, which was predicted as the COOH-terminal amino acid from the nucleotide sequence, was removed. The light subunits were also processed at their COOH-termini by 6 residues. Four or five high mannose type carbohydrate chains were attached to the heavy subunits.
Iwamoto
H
H
Research Institute for Food Science, Kyoto University.
Morita
Y
Y
Kobayashi
T
T
Hasegawa
E
E
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001483:Base Sequence; D004792:Enzyme Precursors / Q000235:genetics; D006595:Hexosamines / Q000032:analysis; D006801:Humans; D008969:Molecular Sequence Data; D009195:Peroxidase / Q000235:genetics
D000596:Amino Acids; D004792:Enzyme Precursors; D006595:Hexosamines; D009195:Peroxidase