The primary structure of Cu-Zn superoxide dismutase from rabbit liver was investigated. The reduced and S-carboxymethylated enzyme was treated with cyanogen bromide, trypsin or Staphylococcus aureus proteinase V8. The resulting peptides were separated by high-performance liquid chromatography and sequenced by automated Edman degradation. With the exception of the N- and C-terminus the complete sequence was established by means of overlapping peptides. The N-terminus is blocked and thus not susceptible to Edman degradation. The amino-acid composition of the tryptic N-terminal peptide corresponds to that of the cytoplasmatic Cu-Zn superoxide dismutases of other mammals investigated. The chromatographic behaviour of these N-terminal peptides on a reversed phase C18 column is also identical, thus suggesting also for the rabbit Cu-Zn superoxide dismutase the N-terminal sequence Ac-Ala-Thr-Lys. The C-terminus was demonstrated to have the sequence -Ile-Ala-Pro by enzymatic degradation with carboxypeptidase Y. The complete amino-acid sequence of the rabbit Cu-Zn superoxide dismutase consists of 152 amino-acids and shows the expected homology to other Cu-Zn enzymes published so far. The aspartate and six histidine residues known to complex the metal ions are conserved at homologous positions. This also applies for the arginine residue near the C-terminus which is supposed to direct the anionic superoxide radical towards the active centre of the enzyme. The amino acid sequence of the rabbit Cu-Zn superoxide dismutase corresponds to those of other mammals in more than 80% of its amino-acid residues. From a total of 152 amino-acid residues the rabbit shares with rat 128, with mouse 130, with horse 127, with pig 126/127, with cattle 130 and with man 131 amino acids in homologous positions. However the Cu-Zn superoxide dismutases of closely related mammals like rats and mice differ in only five amino acid residues of their sequence. A phylogenetic closer relatedness between lagomorphs and rodents than between other orders of mammals, could not be derived from the sequence data given. Rather rodents and lagomorphs are to be considered as two evolutionary independent orders of mammals.
The anti-arthritic activities of various superoxide dismutases and of liposomal bovine Cu-SOD have been compared in the adjuvant induced Lewis Inbred Rat model. Various approaches, including plethysmometric measurements, red cell sedimentation rates, while cell counts, levels of IgA and IgG immunoglobulins and scoring by visual, radiographic and scintigraphic techniques all concord in a demonstration of different activities for different SODs. The most efficient are liposomal bovine Cu-SOD and E. coli Mn-SOD, a moderate activity being shown by free bovine Cu-SOD. Poor or zero results are obtained with human Mn-SOD, human Cu-SOD or the homologous rat Cu-SOD.
In 5 patients, haemolysis was intrasplenic. Red cell deformity could be acquired by foreign red cells transfused into the patient. Association of the two abnormalities (acanthocytosis and glutathion peroxydase deficiency) was necessary for the onset of haemolysis. They progressed in parallel and varied in relation with the severity of the hepatic disease. The relationship between these two abnormalities is unknown but would appear to be dependent upon a factor of hepatic origin.
The role of superoxide radicals and of superoxide dismutases in inflammation is described. Encapsulation of the enzyme in liposomes leads to an increased organ specificity on injection into animals. Preliminary results of medical application are presented.
The complete amino acid sequence of iron superoxide from Escherichia coli has been determined. The sequence was deduced from analysis of peptides obtained after cleavage of the carboxymethylated apoenzyme with trypsin, Stapholococcus aureus protease or CNBr. The polypeptide chain is made up of 192 residues and is easily aligned with the other known amino acid sequences of iron and manganese superoxide dismutases from various sources. The iron superoxide dismutase from E. coli shows a significantly higher homology with the iron enzyme from a different organism than with the manganese isoenzyme from E. coli .
