19th Annual Student Research Conference
Science
Experimental Studies of the Reaction between BHT-QM and Cysteine
Samuel N. Edeh
Dr. Maria Nagan, Dr. Robert G. Dyer, and Dr. Eric V. Patterson, Faculty Mentors
Quinone methides (QMs) are rather reactive intermediates commonly encountered in many chemical and biological processes. QMs react readily with a wide range of biochemical substances, such as peptides, amino acids, thiols and water. This reactivity is due to the protonation of QMs on the carbonyl carbon followed by Michael addition with organic species. QM electrophilicity towards various biochemical compounds has been measured in vitro under physiological conditions. In this experiment, reactions between the nucleophilic amino acid cysteine and an electrophilic QM (2, 6-di-tert-butyl-4-methylene-2, 5-cyclohexadienone, BHT-QM) in aqueous solution were carried out and kinetic measurements were obtained. BHT-QM was produced by oxidation of butylated hydroxytoluene (BHT) using lead dioxide. The alkylation reaction between BHT-QM and cysteine to form an adduct was monitored at physiological pH at a maximal wavelength of 287 nm. The reaction was investigated under pseudo-first order conditions with excess amino acid. The rate of adduct breakdown was used to determine the rate constants.
Keywords: Quinone methide, amino acid, nucleophile, electrophile, Michael addition, alkylation, pseudo-first order, rate constant
Topic(s):Chemistry
Presentation Type: Oral Paper
Session: 9-3
Location: VH 1432
Time: 8:45