An inter-subunit disulfide bond affects affinity of human lung extracellular superoxide dismutase to heparin.
Human extracellular superoxide dismutase (EC-SOD) was purified to homogeneity from lung tissue and the nature of the binding of heparin to EC-SOD was investigated. The enzyme was purified using three column chromatographic steps, and 127 microg of purified EC-SOD was obtained. A specific anti-human EC-SOD antibody was obtained by immunization with the purified enzyme. Western blot analysis of the heparin affinity chromatography product indicated that the presence of the inter-subunit disulfide bond affects the affinity of EC-SOD for heparin. The affinity of EC-SOD for heparin is a very important feature of the enzyme because it controls the distribution of the enzyme in tissues. The present study suggests that, not only the processing of the C-terminal region but inter-subunit disulfide bonds also play a role in determining the tissue distribution of EC-SOD. Moreover, the results obtained here also suggest that the redox state of the tissues might regulate the function of the EC-SOD.
Ookawara
Tomomi
T
Department of Biochemistry, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan. biochook@hyo-med.ac.jp
Eguchi
Hironobu
H
Kizaki
Takako
T
Nakao
Chitose
C
Sato
Yuzo
Y
Imazeki
Nobuo
N
Matsubara
Osamu
O
Ohno
Hideki
H
Suzuki
Keiichiro
K
D015153:Blotting, Western; D002516:Ceramics; D002845:Chromatography / Q000379:methods; D002846:Chromatography, Affinity; D004220:Disulfides / Q000737:chemistry; D017886:Durapatite; D004591:Electrophoresis, Polyacrylamide Gel; D006493:Heparin / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008168:Lung / Q000201:enzymology / Q000473:pathology; D010084:Oxidation-Reduction; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012685:Sepharose / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000378:metabolism*
D004220:Disulfides; D012965:Sodium Chloride; D006493:Heparin; D012685:Sepharose; D017886:Durapatite; D013482:Superoxide Dismutase