Ricin A chain from Ricinus communis (castor bean) 

Agglutination activity is expressed in μg/ml and is determined from serial dilutions in phosphate buffered saline, pH 7.2, of a 1 mg/ml solution. This activity is the lowest concentration to agglutinate a 2% suspension of human erythrocytes after 1 hour incubation at 25°C.

Ricin A chain inactivates the 60 S ribosomal subunit of eukaryotic cells, inhibiting protein synthesis. This toxic activity is independent of the presence of the B chain of ricin.

The carbohydrate moiety of Ricin A chain has been modified using a metaperiodate-cyanoborohydride mixture. The product still inhibits protein synthesis in cell-free systems, and its removal from the blood stream by the liver is markedly decreased. Immunotoxins prepared from deglycosylated Ricin A chain will therefore be more effective in killing target cells.

Ricinus communis toxin (also named RCA₆₀, RCA_II, Ricin D, or RCL III) is a highly toxic protein, mol. wt. ~60 kDa, composed of two chains, A and B, connected by a single disulfide bridge.

Solution in 40% glycerol containing 10 mM phosphate, pH 6.0, 0.15 M NaCl, 10 mM galactose and 0.5 mM dithioerythritol

buffered aqueous glycerol solution

≥250 μg/mL per mL agglutination activity

Protein, 0.5-3.0 mg/mL Lowry-TCA

2-8°C

Thorpe, P.E., et al. Eur. J. Biochem. 147, 197, (1985) abstract

Nicolson, G.L. and Blaustein, J. Biochim. Biophys. Acta 266, 543, (1972)

Nicolson, G.L., et al. Biochemistry 13, 196, (1974)

Thorpe, P.E., et al. Cancer Res. 48, 6396, (1988) abstract

Skilleter, D.N., et al. Biochim. Biophys. Acta 842, 12, (1985) abstract

Wei, C.H. and Koh, C. J. Mol. Biol. 123, 707, (1978)

Lin, T.S. and Li, S.L. Eur. J. Biochem. 105, 453, (1980)

UN 3172 6.1/PG 3

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