Free Radical Metabolites in Arylamine Toxicity

The many roles of myeloperoxidase: From inflammation and immunity to biomarkers, drug metabolism and drug discovery

This review provides a practical guide to myeloperoxidase (MPO) and presents to the reader the diversity of its presence in biology. The review provides a historical background, from peroxidase activity to the discovery of MPO, to its role in disease and drug development. MPO is discussed in terms of its necessity, as specific individuals lack MPO expression. An underlying theme presented throughout brings up the question of the benefit and burden of MPO activity. Enzyme structure is discussed, including accurate masses and glycosylation sites. The catalytic cycle of MPO and its corresponding pathways are presented, with a discussion of the importance of the redox couples of the different states of MPO. Cell lines expressing MPO are discussed and practically summarized for the reader, and locations of MPO (primary and secondary) are provided. Useful methods of MPO detection are discussed, and how these can be used for studying disease processes are implied through the presentation of MPO as a biomarker. The presence of MPO in neutrophil extracellular traps is presented, and the activators of the former are provided. Lastly, the transition from drug metabolism to a target for drug development is where the review concludes.

N-acetyltransferase: the practical consequences of polymorphic activity in man

Over the years, numerous studies have supported the premise that individuals possessing the "slow acetylator" phenotype are more at risk from developing drug side-effects. Most prominent amongst these reports are those concerned with hepatotoxicity and peripheral neuropathy following treatment with isoniazid, lupus-like symptoms during procainamide therapy and experiencing hypersensitivity reactions to the various sulphonamide derivatives. Similarly, "slow acetylators" undergoing heavy exposure to arylamines and related carcinogens are more likely to develop bladder cancer. Contrariwise, there appears a slight risk of "rapid acetylators" developing pancreatic tumours.Other therapeutic agents for which polymorphic N-acetylation plays a minor role in their metabolism have been investigated but any impact of this metabolic difference on clinical efficacy or associated toxicity is still under question. In the search for clues as to the underlying aetiology, patient groups with many disease states have been examined for association with differences in N-acetylation and the majority have provided data that could be interpreted as equivocal. Studies have given contradictory, often opposing, results, calculated risk factors that are (perhaps) just significant but certainly not high, and patients within the cohorts who are always exceptions. Undoubtedly, other as yet unappreciated factors are at play.

One-pot synthesis of secondary amines from alcohols and nitroarenes on TiO2 loaded with Pd nanoparticles under UV irradiation

TiO₂ loaded with Pd nanoparticles, when irradiated by UV light in alcohols with nitroarenes, successfully produces the corresponding secondary amines with almost quantitative yield, via tandem photocatalytic and catalytic reactions.