A Simple, Fast and Portable Method for Electrochemical Detection of Adenine Released by Ricin Enzymatic Activity

Abstract

International authorities classify ricin toxin present in castor seed as a potential agent for use in bioterrorism. Therefore, the detection, identification, and characterization of ricin in various sample matrices are considered necessary actions for risk assessment during a suspected exposure. This study reports a portable electrochemical assay for detecting active ricin based on the adenine electro-oxidation released from herring sperm DNA substrate by its catalytic action. Also, kinetic parameters were calculated, and the values were Km of 3.14 µM and Kcat 2107 min−1. A linear response was found in optimized experimental conditions for ricin concentrations ranging from 8 to 120 ng/mL, and with a detection limit of 5.14 ng/mL. This proposed detection strategy emphasizes the possibility of field detection of active ricin in food matrices and can be applied to other endonucleolytic activities.

Isomorphic Fluorescent Nucleosides Facilitate Real‐Time Monitoring of RNA Depurination by Ribosome Inactivating Proteins

“…stands in contrast to other reported RIP-detecting methods, which all include either stepwise or time-consuming indirect processes (e. g., PCR-based techniques, [29] RNA/DNA probe hybridization, [19,30,31] aptamer-based techniques, [32] enzymecoupled assays, [15,33] mass spectrometry, [34] electrochemistry, [35] etc.). Monitoring a specific biochemical transformation associated with such RNA toxins (i. e., depurination), regardless of the protein immunological fingerprint, thus facilitates pathways for the real-time detection of such cytotoxins and the fabrication of inhibitor discovery tools.…”

Rapid detection of whole active ricin using a surface‐enhanced Raman scattering‐based sandwich immunoassay

“…Active ricin can be measured by in vivo mouse bioassays [ 25 ] and in vitro cytotoxicity assay, [ 26 ] which are time‐consuming or need live animals. Recently, in vitro non‐cell methods have been developed mainly based upon the depurination of RAC catalyzed activity, followed by monitoring the adenine using MS [ 27 ] or electrochemical [ 28 ] or colorimetric assays. [ 29 ] Although RAC catalytic activity assays possess high sensitivity, it is still an indirect identification way for ricin detection, thus with limitation in selectivity.…”