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Updated: Jul 19, 2026

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
Published on: March 28, 2017
Human cyclooxygenase-1b is not the elusive target of acetaminophen
Petra Censarek1, Kerstin Freidel, Thomas Hohlfeld
1Institut für Pharmakologie und Klinische Pharmakologie, Universitätsklinik Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany.
Abstract:
A cyclooxygenase-1 splice variant (cyclooxygenase-1b), cloned from canine brain, was proposed to be an acetaminophen-sensitive enzyme. Unlike in canines, the retention of intron 1 in the human sequence results in a frame shift and predicts a truncation of the protein. We have sought to answer the question whether human cyclooxygenase-1b, if expressed, is a target of acetaminophen. Thus, we studied the pharmacology of complete human cyclooxygenase-1b in which the frame shift was corrected by site-directed mutagenesis (human cyclooxygenase-1bDeltaG). Human cyclooxygenase-1bDeltaG was active but was not inhibited by acetaminophen. In conclusion, full length human cyclooxygenase-1b is clearly not the target of acetaminophen.
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