Mass Spectrometric Detection and Differentiation of Enzymatically Active Abrin and Ricin Combined with a Novel Affinity Enrichment Technique.

Abrin and ricin are toxic proteins produced by plants. Both proteins are composed of two subunits, an A-chain and a B-chain. The A-chain is responsible for the enzymatic activity, which causes toxicity.

DNA Photocleavage in the Near-Infrared Wavelength Range by 2-Quinolinium Dicarbocyanine Dyes.

Here, we report the syntheses of two pentamethine cyanine dyes containing quinolinium rings and substituted with either hydrogen () or bromine () at the carbon. The electron withdrawing bromine atom stabilizes dye in aqueous buffer, allowing complex formation to occur between the dye and double-helical DNA. UV-visible, CD, and fluorescence spectra recorded at low DNA concentrations suggest that dye initially binds to the DNA as a high-order aggregate.