Protein S-nitrosylation regulates the energy metabolism of early postmortem pork using the in vitro model

This research aimed to investigate the regulation of energy metabolism by protein S-nitrosylation utilizing the in vitro muscle glycolysis model. Longissimus thoracis (LT) muscles homogenates were treated with nitric oxide donor NOR-3 ((±)-(E)-4-Ethyl-2-(E)-hydroxyimino-5-nitro-3-hexenamide) and control (0.1 M K 2 HPO 4 ) under different pH conditions (6.5, 6.0 and 5.5) in vitro buffer system for 24 h, respectively. Results indicated that the NOR-3 treatment group had a significantly higher pH decline rate than the control group and resulted in a higher lactate accumulation and glycogen degradation at 24 h compared with the control group ( p < 0.05). Moreover, NOR-3 treatment significantly increased the activities along with S-nitrosylation levels of lactate dehydrogenase and glycogen phosphorylase at pH 6.5 in a concentration-dependent manner ( p < 0.05). In addition, low pH could weaken the NOR-3 treatment effect and inhibit glycolysis rate. Thus, protein S-nitrosylation could play a role in regulating postmortem glycolysis in vitro model even at low pH conditions.