Monday, 23 May 2005
326

This presentation is part of: Biological Chemistry Posters

Biochemical properties of Ricin in Immature Castor seed

Srinivas V.S Chakravartula, New York Medical College, Valhalla, NY and Nagaraj Guttarla, Directorate of Oilseeds Research, Hyderabad, India.

Castor seed consists of two proteins ricin and RCA (ricinus communis agglutinin). The RCA protein is made up of with four subunits having a molecular weight of 1,20, 000 daltons and ricin 62,000 to 65,000 daltons.RCA is not toxic but agglutinates red blood cells of mammals while ricin is toxic(inhibits protein synthesis) but doest not agglutinate red blood cells.One common factor in most of the work reported in the literature involving ricin and RCA toxins is lack of information related to the biochemical properties , physilogical functions at different stages of seed germination and their mode of formation. Keeping these point in view we have studied the chemical properties in immature castor seed.Hemagglutination, SDS-PAGE and UV-spectrometry studies showed total absence of RCA protein in the immature seed.Interestingly, ricin extract on SDS-PAGE showed only one protein band with a molecular weight of 29,000dalton corresponiding to the molecualr weight of A chain of ricn that was seen in the normal seed.Our results have shown that at immature seed level only the toxic moiety of ricin (A chain) is being synthesized first and gradually the RCA and ricin which will be presented.

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