Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.11 (AMPK)
 12,425 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pale, soft, and exudative (PSE) meat has been recognized for decades. Fast glycolysis during early post-mortem stage while the muscle temperature is still high is the cause of PSE meat. To elucidate the molecular mechanism underlying this fast glycolysis in muscle to become PSE meat, post-mortem ATP metabolism, fructose-2,6-diphosphate content, and the activities of AMPK, glycogen phosphorylase, and pyruvate kinase were examined in post-mortem muscle. Earlier and faster post-mortem AMPK activation was responsible for the significantly lower pH and higher lactic acid accumulation (p<0.05) seen in PSE muscle, which resulted in the occurrence of PSE meat. In muscle that became PSE meat, AMPK was activated at 0 h post-mortem and reached maximal activation at 0.5 h post-mortem, whereas AMPK reached maximal activation at 1 h post-mortem in the normal pork loin. Higher fructose-2,6-diphosphate content (p<0.05) was detected in PSE muscle compared to normal muscle at early post-mortem stage. However, no difference in the activities of glycogen phosphorylase and pyruvate kinase, rate-controlling enzymes in glycogenolysis and glycolysis, respectively, was detected between PSE and normal pork loins. Because fructose-2,6-diphosphate is a product of phosphofructokinase-2 (PFK-2), these data suggest that AMPK regulates post-mortem glycolysis through its phosphorylation and activation of PFK-2, which then up-regulates the activity of phosphofructokinase-1 (PFK-1), a key rate-controlling enzyme in glycolysis. Early AMPK activation in PSE muscle is associated with early consumption of ATP, because higher AMP and IMP contents and lower ATP content were detected in PSE meat compared to normal meat. Other mechanisms causing early AMPK activation in PSE meat may exist, which warrants further investigation.
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PMID:Early post-mortem AMP-activated protein kinase (AMPK) activation leads to phosphofructokinase-2 and -1 (PFK-2 and PFK-1) phosphorylation and the development of pale, soft, and exudative (PSE) conditions in porcine longissimus muscle. 1684 49

Pale, soft, and exudative (PSE) meat has been recognized for decades and causes huge economic loss to the meat industry due to its inferior quality. Although it has been well established that fast and excessive glycolysis combined with high temperature in muscle early postmortem is the cause of PSE meat, the molecular mechanisms associated with this abnormal glycolysis remain poorly defined. Our previous studies with mice and pigs suggest that AMPK regulates muscle glycolysis postmortem. To confirm further the role of AMPK in the regulation of postmortem glycolysis, we investigated the effects of intraperitoneal injection of compound C, a specific AMPK inhibitor, on AMPK activation and glycolysis in postmortem longissimus dorsi (LD) muscle of mice. Data showed that intraperitoneal injection of compound C inhibited AMPK activation in postmortem mouse LD muscle. Simultaneously, injection of compound C inhibited glycolysis and increased muscle pH corroborating of our previous observations that postmortem glycolysis is inhibited in AMPK knockout mice. This study firmly supports that AMPK regulates glycolysis in postmortem skeletal muscle and suggests that AMPK can be a target to control postmortem glycolysis, preventing incidence of PSE meat.
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PMID:Compound C, an inhibitor of AMP-activated protein kinase, inhibits glycolysis in mouse longissimus dorsi postmortem. 2206 85