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ricin
- highly toxic lectin & hemagluttinin.
- ricin was originally used in reference to a mixed extract
Epidemiology:
- occurs naturally in seeds (castor beans) & leaves of the castor oil plant, Ricinus commununis.
Structure:
- 2 ricin toxins & 2 hemagluttinins have been identified
- all 4 contain 2 different polypeptide subunits linked by a disulfide bond
- the toxins are dimers of a 30 kD A-chain & a 33 kD B-chain.
Pathology:
- toxicity appears to be largely due to proteins other than a hemagluttinin
Pharmacology:
- ricin has antineoplastic properties
- it shows synergism with daunorubicin, cisplatin & vincristine in treatment of leukemias.
Laboratory:
- ricin in specimen
- ricin toxin in specimen
Isoelectric point: 7.1
UVmax: 280 nm (e = 8500)
General
antineoplastic agent (chemotherapeutic agent)
hemagglutinin
lectin
multisubunit protein
plant protein
toxin (hazardous material, poison)
Properties
SUBUNITS: ricin A
MOTIF: glycosylation site
cysteine residue
MODIFICATION: cysteine residue
ricin B
MOTIF: glycosylation site
cysteine residue
MODIFICATION: cysteine residue
References
- Stedman's Medical Dictionary 27th ed, Williams &
Wilkins, Baltimore, 1999
- Merck Index, I2th ed, Merck & Co, Rahway NJ, 1996 # 8376
- PROSITE :accession PS00275
Components
ricin A
ricin B