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- Vasconcelos IM, Trentim A, Guimarães JA, Carlini CR
- Arch Biochem Biophys 1994 Aug 1 312:2 357-66
- Abstract
- Physicochemical characterization and biological properties of
a new toxic protein isolated from soybeans (Glycine max) is reported.
The purification procedure consisted basically of ammonium sulfate
fractionation, ion exchange, and affinity chromatographies, the
latter being used for the removal of the seed's lectin and of
its trypsin inhibitor. The highly purified protein, designated
soyatoxin, is a single chain acidic protein (pI 4.4-4.6) of 21
kDa, dependent on reduced thiol groups to maintain its solubility
and biological activities. The toxin is a metalloprotein containing
iron, calcium, zinc, and magnesium. Soyatoxin is highly toxic
to mice (LD50 7-8 mg/kg mouse body wt upon intraperitoneal injection).
It produces dyspnoea, tonic-clonic convulsions, and flaccid paralysis
prior to death of intraperitoneally injected mice. Furthermore,
soyatoxin is immunologically related to another toxic protein
(canatoxin), isolated from Canavalia ensiformis seeds, which is
distinct from soyatoxin in containing 18 x 10 kDa noncovalently
bound subunits. Some biological properties including acute intraperitoneal
toxicity, canatoxin-like immunoreactivity, hemagglutination, trypsin
inhibitory activity, induction of platelet release reaction, and
aggregation displayed by soyatoxin were studied and used to differentiate
soyatoxin from soybean lectin and trypsin inhibitors.
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