Abstract
A toxic protein, viscumin, was isolated from extracts of mistletoe by affinity chromatography on acid-treated Sepharose 4B. Viscumin was selectively bound to the column and could be eluted with lactose. It migrated in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate corresponding to Mr = 60,000. In addition, two bands migrating corresponding to Mr = 29,000 and 32,000 were found. After treatment with 2-mercaptoethanol, only 2 bands (Mr = 29,000 and 34,000) were found. Apparently, viscumin consists of two chains which, in some of the molecules, are disulfide-linked. Protection experiments with antiserum against viscumin indicated that the major part of the cytotoxic activity in mistletoe extracts is due to viscumin. Gel filtration experiments on Sephacryl 200 indicated that, at low concentrations, viscumin occurs as a monomer and at higher concentrations as a dimer. Viscumin was found to inhibit protein synthesis in cell-free systems. When the two constituent peptide chains of viscumin were eluted from polyacrylamide gels and tested for ability to inhibit cell-free protein synthesis, this property was found to be associated with the fastest migrating chain, here denoted the A chain. The heavier chain was denoted the B chain. The A chain was found to inhibit protein synthesis by inactivating the ribosomes catalytically. Reconstitution experiments with isolated ribosomal subunits from untreated and A chain-treated ribosomes showed that the 60 S ribosomal subunit was selectively inactivated.
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Claims 9
Claim · model-written summary
Viscumin migrated at Mr = 60,000 in SDS polyacrylamide gel electrophoresis.
- Taxon
- Viscum album
Viscum albumt0 - Gene
- viscumine3
- Outcome
- migrated in polyacrylamide gel electrophoresise2
- Value
- Mr = 60,000e2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e2“It migrated in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate corresponding to Mr = 60,000”
e3“Apparently, viscumin consists of two chains which, in some of the molecules, are disulfide-linked”
Claim · model-written summary
Viscumin was selectively bound to the affinity column and eluted with lactose.
- Taxon
- Viscum albumViscum albumt0
- Gene
- Viscumine1
- Outcome
- selectively bound to the columne1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e1“Viscumin was selectively bound to the column and could be eluted with lactose”
Claim · model-written summary
Viscumin consists of two chains, which are in some molecules disulfide-linked.
- Taxon
- Viscum albumViscum albumt0
- Gene
- viscumine3
- Outcome
- consists of two chainse3
- Qualifier
- disulfide-linkede3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e3“Apparently, viscumin consists of two chains which, in some of the molecules, are disulfide-linked”
Claim · model-written summary
After 2-mercaptoethanol treatment only 2 bands were found, at Mr = 29,000 and 34,000.
- Taxon
- Viscum albumViscum albumt0
- Treatment
- 2-mercaptoethanole4
- Outcome
- only 2 bandse4
- Value
- Mr = 29,000 and 34,000e4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e4“After treatment with 2-mercaptoethanol, only 2 bands (Mr = 29,000 and 34,000) were found”
Claim · model-written summary
The major part of the cytotoxic activity in mistletoe extracts is due to viscumin.
- Taxon
- Viscum albumViscum albumt0
- Gene
- viscumine5
- Outcome
- cytotoxic activity in mistletoe extractse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e5“Protection experiments with antiserum against viscumin indicated that the major part of the cytotoxic activity in mistletoe extracts is due to viscumin”
Claim · model-written summary
Viscumin occurs as a monomer at low concentrations and as a dimer at higher concentrations.
- Taxon
- Viscum albumViscum albumt0
- Gene
- viscumine6
- Outcome
- occurs as a monomere6
- Qualifier
- at low concentrationse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e6“at low concentrations, viscumin occurs as a monomer and at higher concentrations as a dimer”
Claim · model-written summary
Viscumin inhibits protein synthesis in cell-free systems.
- Taxon
- Viscum albumViscum albumt0
- Gene
- Viscumine7
- Outcome
- inhibit protein synthesis in cell-free systemse7
- Direction
- inhibite7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e7“Viscumin was found to inhibit protein synthesis in cell-free systems”
Claim · model-written summary
The A chain inhibits protein synthesis by inactivating ribosomes catalytically.
- Taxon
- Viscum albumViscum albumt0
- Gene
- A chaine1
- Outcome
- inhibit protein synthesise1
- Qualifier
- inactivating the ribosomes catalyticallye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e0“this property was found to be associated with the fastest migrating chain, here denoted the A chain”
e1“The A chain was found to inhibit protein synthesis by inactivating the ribosomes catalytically”
Claim · model-written summary
The A chain-treated ribosomes showed selective inactivation of the 60 S ribosomal subunit relative to untreated ribosomes.
- Taxon
- Viscum albumViscum albumt0
- Treatment
- A chain-treated ribosomese0
- Outcome
- 60 S ribosomal subunite0
- Direction
- selectively inactivatede0
- Comparator
- untreatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Viscum album L. (mistletoe)”
e0“Reconstitution experiments with isolated ribosomal subunits from untreated and A chain-treated ribosomes showed that the 60 S ribosomal subunit was selectively inactivated”