Ceruloplasmin and myeloperoxidase in complex affect the enzymatic properties of each other

Ceruloplasmin (CP), the multicopper oxidase of plasma, interacts with myeloperoxidase (MPO), an enzyme of leukocytes, and inhibits its peroxidase and chlorinating activity. Studies on the enzymatic properties shows that CP behaves as a competitive inhibitor impeding the binding of aromatic substrate...

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Bibliographic Details
Published in:Free radical research 2008, Vol.42 (11-12), p.989-998
Main Authors: Sokolov, Alexej V., Ageeva, Kira V., Pulina, Maria O., Cherkalina, Olga S., Samygina, Valeria R., Vlasova, Irina I., Panasenko, Oleg M., Zakharova, Elena T., Vasilyev, Vadim B.
Format: Article
Language:English
Subjects:
activating enzyme
Catalysis
Ceruloplasmin
Ceruloplasmin - metabolism
Chlorine - metabolism
Enzyme Activation
Humans
Hydrolysis
inhibitory enzyme
Leukocytes - enzymology
limited proteolysis
myeloperoxidase
Oxidoreductases - metabolism
Peroxidase - metabolism
protein-protein interaction
Serine Endopeptidases - metabolism
Spectrophotometry
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Summary:Ceruloplasmin (CP), the multicopper oxidase of plasma, interacts with myeloperoxidase (MPO), an enzyme of leukocytes, and inhibits its peroxidase and chlorinating activity. Studies on the enzymatic properties shows that CP behaves as a competitive inhibitor impeding the binding of aromatic substrates to the active centre of MPO. The contact between CP and MPO probably entails conformational changes close to the p-phenylenediamine binding site in CP, which explains the observed activation by MPO of the substrate's oxidation. CP subjected to partial proteolysis was virtually unable to inhibit activity of MPO. The possible protein-protein interface is comprised of the area near active site of MPO and the loop linking domains 5 and 6 in CP. One of the outcomes of this study is the finding of a new link between antioxidant properties of CP and its susceptibility to proteolysis.
ISSN:1071-5762
1029-2470
DOI:10.1080/10715760802566574