scholarly journals Heparin-induced release of extracellular superoxide dismutase to human blood plasma

1987 ◽  
Vol 242 (1) ◽  
pp. 55-59 ◽  
Author(s):  
K Karlsson ◽  
S L Marklund
Keyword(s):  
Superoxide Dismutase ◽  
Endothelial Cell ◽  
Blood Cells ◽  
Human Blood Plasma ◽  
Extracellular Superoxide Dismutase ◽  
Cell Surfaces ◽  
Sod Activity ◽  
No Release ◽  
Plasma Phase ◽  
Heparin Affinity

Extracellular superoxide dismutase (SOD) has previously been shown to be the major SOD isoenzyme in extracellular fluids. Upon chromatography on heparin-Sepharose it was separated into three fractions: A, without affinity; B, with intermediate affinity; and C, with relatively strong heparin affinity. Intravenous injection of heparin leads to a prompt increase in plasma extracellular-superoxide-dismutase (EC-SOD) activity. Heparin induces no release of EC-SOD from blood cells, nor does it activate EC-SOD in plasma, indicating that the source of the released enzyme is the endothelial-cell surfaces. No distinct saturation could be demonstrated in a dose-response curve up to 200 i.u. of heparin per kg body weight, showing that the releasing potency of heparin is lower for EC-SOD than for previously investigated heparin-released factors. Chromatography of human plasma on heparin-Sepharose shows nearly equal amounts of EC-SOD fractions A, B and C. Heparin induces specifically the release of fraction C. The findings point to the existence of an equilibrium of EC-SOD fraction C between the plasma phase and endothelial-cell surfaces. The major part of EC-SOD in the vasculature seems to be located on endothelial-cell surfaces.

scholarly journals Substitution of glycine for arginine-213 in extracellular-superoxide dismutase impairs affinity for heparin and endothelial cell surface

1996 ◽  
Vol 313 (1) ◽  
pp. 235-239 ◽  
Author(s):  
Tetsuo ADACHI ◽  
Harutaka YAMADA ◽  
Yasukazu YAMADA ◽  
Naoaki MORIHARA ◽  
Naoya YAMAZAKI ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Superoxide Dismutase ◽  
Endothelial Cell ◽  
Cell Surface ◽  
Extracellular Superoxide Dismutase ◽  
Endothelial Cell Surface ◽  
High Level Group ◽  
High Level ◽  
Heparin Affinity ◽  
Level Group

Extracellular-superoxide dismutase (EC-SOD) levels in sera divide into two discontinuous groups: a low-level group below 400 ng/ml and a high-level group above 400 ng/ml [Adachi, Nakamura, Yamada, Futenma, Kato and Hirano (1994) Clin. Chim. Acta 229, 123-131]. Molecular genetic studies have shown that the donors in the high-level group have a single base substitution generating the exchange of glycine for arginine-213 (R213G) in the heparin-binding domain of EC-SOD [Sandström, Nilsson, Karlsson and Marklund (1994) J. Biol. Chem. 269, 19163-19166; Yamada, Yamada, Adachi, Goto, Ogasawara, Futenma, Kitano, Hirano and Kato (1995) Jpn. J. Hum. Genet. 40, 177-184]. The serum EC-SOD level in homozygote subjects was significantly higher than that in heterozygotes and in normal subjects. Serum EC-SOD from heterozygotes and homozygotes had equally decreased affinity for heparin, as judged by heparin-HPLC, as compared with that from normal donors. This result suggests that the serum EC-SOD in heterozygotes was mainly composed of the mutant form which has reduced heparin affinity. On the other hand, fibroblast cells derived from heterozygote subjects generated mRNA of both normal and mutant EC-SOD (m-EC-SOD), and expressed the corresponding proteins. EC-SOD is a tetrameric enzyme, and in heterozygote donors would be heterogeneous with regard to the constitution of normal and mutant subunits. The enzyme form consisting of only mutant subunits, the form with the weakest heparin affinity, can be preferentially driven out to the plasma phase, because EC-SOD in the vasculature exists in equilibrium between plasma and the endothelial cell surface. The binding of m-EC-SOD to bovine aortic endothelial cells was about 50-fold less than that of normal EC-SOD. This result suggests that the binding of m-EC-SOD to vascular endothelial cells is much decreased in vivo, which causes a high level of serum EC-SOD.

Secretion of extracellular superoxide dismutase in neonatal lungs

2000 ◽  
Vol 279 (5) ◽  
pp. L977-L984 ◽  
Author(s):  
Eva Nozik-Grayck ◽  
Christine S. Dieterle ◽  
Claude A. Piantadosi ◽  
Jan J. Enghild ◽  
Tim D. Oury
Keyword(s):  
Superoxide Dismutase ◽  
Disulfide Bonds ◽  
Developmental Regulation ◽  
Extracellular Superoxide Dismutase ◽  
Sod Activity ◽  
Rabbit Lung ◽  
Pulmonary Response ◽  
Extracellular Compartment ◽  
Neonatal Lung ◽  
Heparin Affinity

Extracellular superoxide dismutase (EC-SOD), the only known enzymatic scavenger of extracellular superoxide, may modulate reactions of nitric oxide (NO) in the lungs by preventing reactions between superoxide and NO. The regulation of EC-SOD has not been examined in developing lungs. We hypothesize that EC-SOD plays a pivotal role in the response to increased oxygen tension and NO in the neonatal lung. This study characterizes rabbit EC-SOD and investigates the developmental regulation of EC-SOD activity, protein expression, and localization. Purified rabbit EC-SOD was found to have several unique biochemical attributes distinct from EC-SOD in other species. Rabbit lung EC-SOD contains predominantly uncleaved subunits that do not form disulfide-linked dimers. The lack of intersubunit disulfide bonds may contribute to the decreased heparin affinity and lower EC-SOD content in rabbit lung. EC-SOD activity in rabbit lungs is low before birth and increases soon after gestation. In addition, the enzyme is localized intracellularly in preterm and term rabbit lungs. Secretion of active EC-SOD into the extracellular compartment increases with age. The changes in EC-SOD localization and activity have implications for the neonatal pulmonary response to oxidative stress and the biological activity of NO at birth.

scholarly journals Proteolytic modification of the heparin-binding affinity of extracellular superoxide dismutase

1993 ◽  
Vol 290 (2) ◽  
pp. 623-626 ◽  
Author(s):  
K Karlsson ◽  
A Edlund ◽  
J Sandström ◽  
S L Marklund
Keyword(s):  
Superoxide Dismutase ◽  
Binding Affinity ◽  
Heparan Sulphate ◽  
Limited Proteolysis ◽  
Size Exclusion ◽  
Extracellular Superoxide Dismutase ◽  
Heparin Binding ◽  
Binding Domains ◽  
Heparin Affinity

The heparin-binding affinity of the tetrameric extracellular superoxide dismutase (EC-SOD) is a result of the cooperative effect of the heparin-binding domains of the subunits, located in the hydrophilic, strongly positively charged C-terminal ends. EC-SOD C, the high-heparin-affinity type, exposed to immobilized trypsin and plasmin was found to rapidly lose its affinity for heparin, without any loss of enzymic activity or major change in molecular mass as judged by size-exclusion chromatography. Heparin and dextran sulphate 5000 inhibited the proteolysis, suggesting that EC-SOD C sequestered by heparan sulphate proteoglycan in vivo is partially protected against proteolysis. The loss of heparin-affinity occurred with the stepwise formation of intermediates, and the pattern upon chromatography on heparin-Sepharose and subsequent immunoblotting was compatible with the notion that the changes are due to sequential truncations of heparin-binding domains from subunits composing the EC-SOD tetramers. A similar pattern with intermediates and apparent truncations has previously been found with EC-SOD of human plasma. The findings show that the unique design of the heparin-binding domain of EC-SOD allows easy modification of the heparin-affinity by means of limited proteolysis, and suggest that such proteolysis is a major contributor to the heterogeneity in heparin-affinity of EC-SOD in mammalian plasma.

scholarly journals Human extracellular superoxide dismutase is a tetramer composed of two disulphide-linked dimers: a simplified, high-yield purification of extracellular superoxide dismutase

1996 ◽  
Vol 317 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Tim D. OURY ◽  
James D. CRAPO ◽  
Zuzana VALNICKOVA ◽  
Jan J. ENGHILD
Keyword(s):  
Superoxide Dismutase ◽  
Limited Proteolysis ◽  
Exchange Chromatography ◽  
Disulphide Bond ◽  
High Yield ◽  
Human Aorta ◽  
Extracellular Superoxide Dismutase ◽  
Heparin Binding ◽  
Sod Activity ◽  
Native Page

Studies examining the biochemical characteristics and pharmacological properties of extracellular superoxide dismutase (EC SOD) have been severely limited because of difficulties in purifying the enzyme. Recently EC SOD was found to exist in high concentrations in the arteries of most mammals examined and it is the predominant form of SOD activity in many arteries. We now describe a three-step, high-yield protocol for the purification of EC SOD from human aorta. In the first step, the high affinity of EC SOD for heparin is utilized to obtain a fraction in which EC SOD constitutes roughly 13% of the total protein compared with only 0.3% of that of the starting material. In addition, over 80% of the original EC SOD activity present in the aortic homogenate was retained after the first step of purification. EC SOD was further purified using a combination of cation- and anion-exchange chromatography. The overall yield of EC SOD from this purification procedure was 46%, with over 4 mg of EC SOD obtained from 230 g of aorta. Purified EC SOD was found to exist predominantly as a homotetramer composed of two disulphide-linked dimers. However, EC SOD was also found to form larger multimers when analysed by native PAGE. It was shown by urea denaturation that the formation of multimers increased the thermodynamic stability of the protein. Limited proteolysis of EC SOD suggested that there is one interchain disulphide bond covalently linking two subunits. This disulphide bond involves cysteine-219 and appears to link the heparin-binding domains of the two subunits.

scholarly journals Heparin-Affinity of Human Extracellular-Superoxide Dismutase in the Brain.

2001 ◽  
Vol 24 (2) ◽  
pp. 191-193 ◽  
Author(s):  
Tetsuo ADACHI ◽  
Masayuki YAMAMOTO ◽  
Hirokazu HARA
Keyword(s):  
Superoxide Dismutase ◽  
Extracellular Superoxide Dismutase ◽  
Heparin Affinity ◽  
The Brain

Gene transfer of extracellular superoxide dismutase improves endothelial function in rats with heart failure

2005 ◽  
Vol 289 (2) ◽  
pp. H525-H532 ◽  
Author(s):  
Shinichiro Iida ◽  
Yi Chu ◽  
Joseph Francis ◽  
Robert M. Weiss ◽  
Carol A. Gunnett ◽  
...  
Keyword(s):  
Heart Failure ◽  
Superoxide Dismutase ◽  
Risk Factor ◽  
Endothelial Dysfunction ◽  
Gene Transfer ◽  
Endothelial Function ◽  
Mesenteric Artery ◽  
Extracellular Superoxide Dismutase ◽  
Protective Effects ◽  
Sod Activity

Oxidative stress is associated with endothelial dysfunction in heart failure. The goals of this study were to determine whether 1) gene transfer of extracellular superoxide dismutase (ecSOD) reduces levels of superoxide and improves endothelial function in the aorta and mesenteric artery in rats with heart failure, and 2) the heparin-binding domain (HBD) of ecSOD, by which ecSOD binds to cells, is required for protective effects of ecSOD. Seven weeks after coronary ligation, in rats with heart failure and sham-operated rats, we injected adenoviral vectors intravenously that express ecSOD, ecSOD with deletion of the HBD (ecSODΔHBD), or a control vector. Four days after injection of viruses, responses to acetylcholine, ADP, and sodium nitroprusside were examined in rings of the aorta and mesenteric artery. ecSOD bound to endothelium and increased SOD activity in the aorta after gene transfer of ecSOD, not ecSODΔHBD. Gene transfer of ecSOD, but not ecSODΔHBD, reduced levels of superoxide and improved relaxation to acetylcholine and ADP in the aorta and mesenteric artery from rats with heart failure. Improvement of relaxation to acetylcholine in the mesenteric artery from rats with heart failure after gene transfer of ecSOD was mediated in part by hydrogen peroxide. The major finding of this study is that the HBD of ecSOD is necessary for protection against endothelial dysfunction in rats with heart failure. We speculate that a common gene variant in the HBD of ecSOD, which is a risk factor for ischemic heart disease, may be a risk factor for vascular maladaptation and endothelial dysfunction in heart failure.

scholarly journals Heparin-affinity patterns and composition of extracellular superoxide dismutase in human plasma and tissues

1993 ◽  
Vol 294 (3) ◽  
pp. 853-857 ◽  
Author(s):  
J Sandström ◽  
K Karlsson ◽  
T Edlund ◽  
S L Marklund
Keyword(s):  
Superoxide Dismutase ◽  
Umbilical Cord ◽  
Heparan Sulphate ◽  
Complex Mixture ◽  
Distribution Volume ◽  
Extracellular Superoxide Dismutase ◽  
Heparin Binding ◽  
Intracellular Space ◽  
Heparin Binding Domain ◽  
Heparin Affinity

The tetrameric extracellular superoxide dismutase (EC-SOD) in human tissues and plasma has previously been found to be heterogenous with regard to heparin affinity and could be divided into at least three classes: A, lacking heparin affinity; B, with weak affinity; and C, with strong affinity. Using rigorous extraction conditions and an extensive set of anti-proteolytic agents, tissue EC-SOD is now shown to be almost exclusively of native homotetrameric C-class. Plasma EC-SOD on the other hand is shown to be mainly composed of a complex mixture of heterotetramers with modifications probably residing in the C-terminal heparin-binding domain. Proteolytic truncations appear to be a major cause of this heterogeneity. The findings suggest that, since 99% of the EC-SOD in the human body exists in the extravascular space of tissue, EC-SOD is primarily synthesized in tissues and secreted as homotetrameric native EC-SOD C. This tissue EC-SOD C should exist almost completely sequestered by heparin sulphate proteoglycans. C-terminal modifications subsequently occurring in the EC-SOD C would weaken the binding to heparan sulphate proteoglycan, facilitate entrance to the vasculature through capillaries and lymph flow, and finally result in the heterogeneous plasma EC-SOD pattern. With the new extraction and analysis procedure, the tissue content of EC-SOD is found to be higher than previously reported. It is found, for example, when compared with Mn-SOD, to be higher in umbilical cord and uterus, about equal in placenta and testis and as high as that of CuZn-SOD in umbilical cord. The findings suggest that the protection level against superoxide radicals provided by EC-SOD in the tissue interstitial space, given the small distribution volume, is not much less prominent than that bestowed on the intracellular space by CuZn-SOD and Mn-SOD.

scholarly journals Non-enzymic glycation of human extracellular superoxide dismutase

1991 ◽  
Vol 279 (1) ◽  
pp. 263-267 ◽  
Author(s):  
T Adachi ◽  
H Ohta ◽  
K Hirano ◽  
K Hayashi ◽  
S L Marklund
Keyword(s):  
Superoxide Dismutase ◽  
Heparan Sulphate ◽  
Normal Subjects ◽  
Enzymic Activity ◽  
Diabetic Patients ◽  
Extracellular Superoxide Dismutase ◽  
Heparin Binding ◽  
A Minor ◽  
Heparin Affinity

The secretory enzyme extracellular superoxide dismutase (EC-SOD) is in plasma heterogenous with regard to heparin-affinity and can be divided into three fractions, A that lacks affinity, B with intermediate affinity and C with high affinity. The C fraction forms an equilibrium between the plasma phase and heparan sulphate proteoglycan on the surface of the endothelium. In vitro EC-SOD C could be time-dependently glycated. The enzymic activity was not affected in glycated EC-SOD, but the high heparin-affinity was lost in about half of the studied glycated fraction. Addition of heparin decreased the glycation in vitro, and EC-SOD C modified with the lysine-specific reagent trinitrobenzenesulphonic acid could not be glycated in vitro. The findings suggest that the glycation sites are localized rather far away from the active site and may occur on lysine residues in the heparin-binding domain in the C-terminal end of the enzyme. The proportion of glycated EC-SOD in serum of diabetic patients was considerably higher than in normal subjects. Of the subfractions, EC-SOD B was by far the most highly glycated, followed by EC-SOD A. EC-SOD C was glycated only to be a minor extent. The findings suggest that glycation is one of the factors that contribute to the heterogeneity in heparin-affinity of plasma EC-SOD. Since this phenomenon is increased in diabetes, the cell-surface-associated EC-SOD may be decreased in this disease, increasing the susceptibility of cells to superoxide radicals produced in the extracellular space.

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