Recombinant Porcine 12-Lipoxygenase Catalytic Domain: Effect of Inhibitors, Selectivity of Substrates and Specificity of Oxidation Products of Linoleic Acid

Abstract

Lipoxygenase (LOX) is a major endogenous enzyme for the enzymatic oxidation of lipids during meat storage and meat product manufacturing. In the present work, some characteristics, i.e., effects of inhibitors, selectivity of substrates and specificity of oxidation products, were studied using recombinant porcine 12-lipoxygenase catalytic domain (12-LOXcd). Several familiar inhibitors were found inhibit the activity of recombinant porcine 12-LOXcd;nordihydroguaiaretic acid demonstrated the strongest inhibitory effect. The enzyme could oxygenate common polyunsaturated fatty acids, and showed the highest affinity to linoleic acid (LA), followed by arachidonic acid (AA), linolenic acid (LN) and docosahexaenoic acid (DHA). Under the action of porcine 12-LOXcd, LA was oxidized into four hydroxyoctadecadienoic acid (HODE) isomers, i.e., 13-Z,E-HODE, 13-E,E-HODE, 9-Z,E-HODE and 9-E,E-HODE. Variation of pH not only affected the yield of LA oxidation products, but also the distribution of HODE isomers. These results indicated that endogenous LOX activity and LOX-catalyzed lipid oxidation can be regulated during meat storage and meat product manufacturing.

RETRACTED: Integrated the embedding delivery system and targeted oxygen scavenger enhances free radical scavenging capacity

“…One lipoxygenase catalyzes the oxidation of triglycerides, while the other can only catalyze the oxidation of fatty acids. The active center of lipoxygenase contains an iron atom, essential fatty acids are their primary oxidation substrates, so these enzymes can selectively catalyze the oxidation of polyunsaturated fatty acids ( Xu et al, 2022 ).…”

Changes in volatile compounds and lipid oxidation in various tissues of Nile tilapia (Oreochromis niloticus) during ice storage

“…Among various herring by‐products, the head (gills‐on) had remarkable higher LOX activity than skin‐on fillet, viscera + belly flap, backbone, and tail, which made it more susceptible to oxidation (Wu et al., 2022). In addition, a higher amount of linoleic acid and arachidonic acid, as the most preferred substrates for LOX, in the fish gills might be associated with higher activity of the enzyme (Xu et al., 2022). LOX with affinity to arachidonic acid, linoleic acid, and eicosapentaenoic acid (EPA) has been determined in rabbit fish viscera, sardine skin, and mackerel gills (Hong, 1994; Jiarpinijnun et al., 2022; Mohri et al., 1992), in which sardine skin LOX oxidized linoleic acid more efficiently than arachidonic acid and EPA, while LOX in mackerel gills showed the highest reactivity toward EPA.…”

VNS‐mediated α7nAChR signaling promotes SPM synthesis via regulation of netrin‐1 expression during LPS‐induced ALI

“…A study by Xu et al proposed that pH alterations can manipulate the substrate direction by modifying the dissociation degree of specific amino acids in porcine lipoxygenase, thereby leading to a shift in the distribution of oxidation products. 63 Higher eukaryotic LOX possesses a secondary structural domain at the N-terminal end, known as the polycystin-1, lipoxygenase, alpha-toxin (PLAT) domain which is implicated in the regulation of LOX substrate selectivity via membrane binding and fatty acid metathesis. 64 As for EPA, we detected an increase only in the PNU-282987 + LPS group; no change was observed in the other groups.…”