Lectins from Abrus Precatorius and Ricinus Communis

[摘要] When equimolar amounts of purified homologous A- and B-chains from abrin or ricin are mixed and dialyzed to remove 2-mercaptoethanol, the disulfide bridge between the chains reforms and fully toxic molecules are reconstituted. In a similar manner, when heterologous chains are mixed and dialyzed, the toxic hybrid molecules abrin A/ricin B or ricin A/abrin B are formed in good yield. Stable hybrid molecules were not formed between the two A-chains or the two B-chains.Whereas rabbit anti-abrin and anti-ricin sera each neutralizes only its homologous toxin, neither antitoxin can distinguish between the hybrid toxins. On the other hand, antibodies specifically directed against determinants on A- or B-chains readily distinguish between the two hybrids. Neutralization by antisera of the toxic effects of abrin, ricin, and their hybrids on protein synthesis in HeLa cell cultures has been studied quantitatively.The results are discussed in relation to other interspecies hybrid molecules and in relation to the mode of action of certain glycoprotein tropic hormones.

[学科分类] 生物科学（综合）