Biomedical subjects

A S Olsson

Publications and source records attributed to A S Olsson.

4 recordsLinked to original sources

PubMed1980

Interaction between human pancreatic elastase and plasma protease inhibitors.

1 ml of human serum inhibits about 0.9 mg of purified human pancreatic elastase owing to complexation with alpha 1-antitrypsin and alpha 2-macroglobulin. On addition to serum, elastase is preferentially bound by alpha 2-macroglobulin. The complexes between elastase and alpha 1-antitrypsin and alpha 2-macroglobulin, respectively, migrate as alpha 2-globulin on agarose gel electrophoresis. Elastase bound by alpha 1-antitrypsin is precipitated by antibodies against enzyme as well as inhibitor, while the alpha 2-macroglobulin-bound elastase is only precipitated by antibodies against the inhibitor. The molar combining ratio for elastase/alpha 1-antitrypsin is 1:1 and for elastase/alpha 2-macroglobulin 2:1. The elastase bound by alpha 2-macroglobulin retains its activity against low molecular weight substrates, while that bound by alpha 1-antitrypsin is enzymologically inactive.

Humans↗

PubMed1978

Studies on the influence of Trasylol on the partition of trypsin between the human plasma protease inhibitors in vitro.

The distribution of trypsin between the protease inhibitors of human serum with and without Trasylol was studied in vitro. 1) Trypsin was preferentially bound by alpha2-macroglobulin on addition of small amounts of the enzyme to normal serum in both the presence and absence of Trasylol in a molar concentration equal to that of alpha2-macroglobulin. 2) On saturation of alpha2-macroglobulin, a considerable amount of trypsin was bound by Trasylol even when most of the serum alpha1-antitrypsin was in a free form. 3) In reaction mixtures containing small amounts of trypsin, Trasylol was identified in a free form as well as in complex with trypsin-alpha2-macroglobulin complex and to a limited extent with trypsin. 4) With larger amounts of trypsin, sufficient to saturate alpha2-macroglobulin, increasing amounts of Trasylol were bound to trypsin. The relative amount of Trasylol bound to trypsin-alpha2-macroglobulin complexes was now smaller. This was explained by a higher affinity (or binding rate) of Trasylol for trypsin than for trypsin-alpha2-macroglobulin complexes. 5) Trypsin-Trasylol complexes showed no signs of dissociation after 5 h incubation at 37 degrees C in serum.

Aprotinin↗

PubMed1978

Immunoreactive granulocyte elastase in human serum.

A specific radioimmunoassay has been developed for determination of human granulocyte elastase in blood. THE granulocyte elastase employed as radioiodinated tracer in the assay was inactivated with diisopropylfluorophosphate in order to prevent binding of the tracer to the serum inhibitors alpha2-microglobulin and alpha1-anti-trypsin, while still retaining its immunoreactivity. The labelled tracer showed, however, a pronounced tendency to nonspecific binding to serum proteins such as albumin and alpha2-macroglobulin and also to the Sephadex particles. The binding of the labelled tracer to alpha2-macroglobulin caused a false increase in the immunoreactive granulocyte elastase in serum. But the binding of the labelled tracer and its consequences could be circumvented by increasing the NaCl concentration of the reaction mixtures and/or gel filtration buffers. Freshly drawn normal human serum contains about 135 microgram granulocyte elastase/l measured as diisopropylfluorophosphate-inactivated granulocyte elastase. The results of experiments in which serum was fractionated by Sephadex G-100 gel filtration suggest that essentially all of the immunoreactive material in normal human serum is granulocyte elastase bound by alpha1-antitrypsin. This finding implies that granulocyte elastase is released from the cells in an active form and then rapidly bound by the inhibitors.

Granulocytes↗

PubMed1976

Purification and partial characterization of human pancreatic elastase.

1) An elastolytic enzyme has been isolated from human pancreatic juice. The concentration of the enzyme was about 0.6 mg/ml corresponding to about 10% of the protein concentration of the juice. 2) The purification procedure included chromatography on Sephadex G-25 followed by ion-exchange chromatography on SP-Sephadex C-50 at pH 6.0, affinity chromatography on Trasylol-Sepharose 4-B and a final ion-exchange chromatography on SP-Sephadex at pH 7.6. The yield was about 50%. 3) The elastase isolated was homogeneous in analytical disc electrophoresis and showed a single protein component with a molecular weight of 26 300 in dodecylsulfate-electrophoresis. There are similarities in the amino acid compositions of human and porcine pancreatic elastases. 4) The human enzyme has a lower activity on elastin than porcine elastase but similar activities on casein and fibrin. The Km value for Boc-Ala-ONp was 5.13 X 10(-4) M. The elastase isolated was 98% active, as judged from active site titration. 5) The results of immunodiffusion studies of activated pancreatic juice and duodenal juice with specific elastase-directed antibodies indicate that the purified enzyme was the single elastolytic enzyme present. 6) It is a cationic protein without any carbohydrate. The activation of the pro-elastase resulted in the formation of an active enzyme with a higher isoelectric point than the zymogen.

Amino Acids↗