Contribution of the phosphagen system to postmortem muscle metabolism in AMP-activated protein kinase 纬3 R200Q pig Longissimus muscle

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• 作者：Tracy L. Scheffler ; Steven C. Kasten ; Eric M. Engl ; Jason M. Scheffler ; David E. Gerrard
• 关键词：AMP-activated protein kinase ; Phosphagen system ; 尾-Guanidinopropionic acid ; Creatine kinase ; Postmortem metabolism
• 刊名：Meat Science
• 出版年：February, 2014
• 年：2014
• 卷：96
• 期：2_part_PA
• 页码：876-883
• 全文大小：810 K

文摘

Pigs with the AMP-activated protein kinase 纬3 R200Q (AMPK纬3^R200Q) mutation generate pork with low ultimate pH (pH_u). We hypothesized that reducing muscle creatine (Cr) and phosphocreatine (PCr) may accelerate postmortem ATP consumption and prevent extended pH decline in AMPK纬3^R200Q longissimus muscle. Wild type and AMPK纬3^R200Q pigs were assigned to control diet or diet supplemented with the creatine analog 尾-guanidinopropionic acid (尾-GPA, 1%) for 2 wk. 尾-GPA reduced muscle PCr (P = 0.006) and total Cr (P < 0.0001). In general, AMPK纬3^R200Q + 尾-GPA exhibited more rapid metabolism than control, AMPK纬3^R200Q, and 尾-GPA treatment, evidenced by more rapid loss of ATP, more rapid increase in IMP, and decreased pH during the first 90 min postmortem. Overall, pH_u was similar despite elevated glycogen (AMPK纬3^R200Q), reduced total Cr (尾-GPA) or both (AMPK纬3^R200Q + 尾-GPA). Thus, reducing muscle phosphagens did not affect pH_u in AMPK纬3^R200Q muscle, but it hastened ATP depletion and pH decline.