Structural considerations on lipoxygenase function, inhibition and crosstalk with nitric oxide pathways

Area of Science:

• Biochemistry
• Enzymology
• Inflammation research

Background:

• Lipoxygenases (LOX) are key enzymes in the eicosanoid cascade, utilizing polyunsaturated fatty acids (PUFA) like arachidonic acid (AA) to produce inflammatory mediators.
• Mammalian LOXs play a critical role in inflammatory responses, synthesizing leukotrienes (LT) and other oxidized lipids.

Purpose of the Study:

• To review the structural and kinetic aspects of LOX selectivity.
• To explore the implications of LOX inhibition and interactions with nitric oxide (NO) and nitroalkene pathways in both basic and clinical contexts.

Main Methods:

• Literature review focusing on LOX structure, kinetics, and interactions with NO and nitroalkenes.
• Analysis of the interplay between LOX, NO, reactive nitrogen species (RNS), and nitroalkenes (NO2FA).

Main Results:

• NO can inhibit LOX activity by reacting with lipid peroxyl radicals or competing with O2 at the active site, offering a protective role against lipid peroxidation.
• RNS, such as nitrogen dioxide (NO2), can react with LOX-generated species to form nitroalkenes (NO2FA), which may exert anti-inflammatory effects by interacting with LOX amino acids.
• Nitro-oxidative conditions can alter LOX substrate availability, potentially redirecting PUFA metabolism towards anti-inflammatory or pro-resolutive pathways.

Conclusions:

• LOX activity and selectivity are influenced by their structure and kinetics.
• The interaction between LOX, NO, and nitroalkenes presents a complex regulatory network with significant implications for inflammation.
• Modulating these pathways offers potential therapeutic strategies for inflammatory diseases.