An elastolytic enzyme has been isolated from dog granulocyte leukocytes. The purification procedure included preparation of the granula fraction, chromatography on Sephadex G‐75 and ion‐exchange chromatography on SP‐Sephadex C‐50 at pH 6.0. The elastase isolated was homogeneous in analytical disc electrophoresis and showed in sodium dodecylsulfate electrophoresis a single protein component with the molecular weight of 24800. The. enzyme lacked tyrosine and lysine and the N‐terminal amino acid was phenylalanine. No carbohydrate or sialic acid were detected. The dog granulocyte elastase showed similar activities as human granulocyte elastase on elastin and fibrin. The Km value for 3‐carboxypropionyl‐l‐alanyl‐l‐alanyl‐l‐alanyl‐p‐nitroanilide was 2.50 mM and the pH optimum 8.5. The elastase preparation obtained was 99.5%, active as judged from active‐site titration. The enzyme is a cationic protein and shows pronounced trailing on agarose gel electrophoresis. A monospecific antiserum against the purified enzyme was produced in rabbits.

Two patients with life-threatening disseminated intravascular coagulation (DIC) syndrome, one caused by Gram-negative bacteria and one by premature separation of the placenta, are described. Specific substitution was given by antithrombin III concentrate and AHF-Kabi, a low purity factor VIII concentrate containing native von Willebrand factor and factor XIII. The treatment quickly returned the extremely low levels of antithrombin III, factor VIII:C, fibrinogen and factor XIII, initially found, to normal, and also returned the multimeric pattern of von Willebrand factor to normal. This resulted in diminished bleeding, enabling surgical treatment of the underlying disease.

The lysosome-like granules of human and canine granulocytes contain an enzyme with elastinolytic activity. The enzymatic behaviour of these elastases was further characterized using the protein substrates elastin-orcein and azocasein and the synthetic substrates tert. -butyloxycarbonyl-alanine p-nitrophenylester (Boc-Ala-ONp) and 3-carboxypropionyl-L-alanyl-L-alanyl-L-alanine p-nitroanilide (Suc-Ala 3 -NHNp) in photometric assays. The affinities of the granulocyte elastases and of porcine pancreatic elastase to these substrates are very similar, e.g. human granulocyte elastase: K M (Boc-AlaONp) = 0.35mM, KM (Suc-Ala 3 -NHNp) = 1.25mM, porcine pancreatic elastase: K M

Leukocyte elastase was demonstrated immunohistochemically not only in PMN-leukocytes in subcutaneous abscesses but also in scattered macrophage-like cells which in addition contained immunoreactive α₁-proteinase inhibitor (α₁PI) and α₂-macroglobulin (α₂M). These cells were located mainly in the marginal region of the abscesses. It is concluded that the intracellular deposits in the macrophage-like cells represent phagocytized elastase and/or elastase-α₁PI and elastase-α₂M complexes. A contributing, local production of the inhibitor is, however, not excluded by the present findings.

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