Monoclonal antibodies as catalysts for cyanide removal

Technical Report · Thu May 13 00:00:00 EDT 1993

OSTI ID:7234840

Cook, C E; Whisnant, C C; Miller, D B; Allen, D A; Basta, P V

We have shown that hydrogen cyanide reacts with alpha, beta-unsaturated ketones to form stable compounds under physiological conditions (temperature, pH). Although spontaneous reaction is too slow for protection against cyanide intoxication, rate enhancement in the presence of a suitable catalyst would permit the use of alpha, beta-unsaturated ketones (enones) as prophylactics for cyanide exposure. Based on the accepted mechanism for this 1,4-addition reaction, we have designed and synthesized sized a transition state analog (TSA), conjugated it to protein and used the conjugate to produce more than 300 monoclonal antibodies which bind the TSA. Approximately 10% of these antibodies have been purified from ascites and tested for catalysis of the addition reaction of cyanide to enone. Product formation was measured by HPLC. Four antibodies have been found which significantly enhance the initial velocity of the reaction. The TSA markedly diminishes the reaction velocity, indicating the involvement of the antibody binding site in the observed enhancement. Preliminary kinetic analysis on one antibody gave values of K sub (enone) and K sub KCN 51 uM and 9.6 mM, respectively. The value of k sub (cat) was 2.33 hr-1. The data suggest a rate enhancement of 2 x 10 to the 4th power for the encounter of the enone with the antibody-cyanide complex, whereas the rate enhancement for encounter of cyanide with the antibody-enone complex is 70. To utilize the potential of genetic engineering for modifying the proper-lies of anti-TSA monoclonal antibodies, we are cloning heavy and light chain genes for sequencing and subsequent site-specific mutagenesis.

• Research Organization: Research Triangle Inst., Durham, NC (United States)
• OSTI ID: 7234840
• Report Number(s): AD-P-008839/3/XAB; CNN: DAMD17-90-C-0023
• Resource Relation: Other Information: This article is from 'Proceedings of the Medical Defense Bioscience Review (1993) Held in Baltimore, Maryland on 10-13 May 1993. Volume 2', AD-A275 668, p841-850
• Country of Publication: United States
• Language: English

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