Effect of stress on key proteins in energy metabolism of lamb

Abstract

A major goal in meat science is to determine the pre- and post-mortem conditions that will provide consistent high-quality meat. This is particularly important for New Zealand where most of the meat is exported to countries with stringent criteria. Earlier studies have shown that acute exercise stress causes reproducible changes in lamb meat quality associated with high pH [1]. It has also been shown that muscle type influences the nature and extent of these changes. A potential mechanism for these changes is differences in energy metabolism caused by changes in key enzymes associated with glycolysis. Glycolysis is a key pathway in post-mortem as oxygen supply to the muscle ceases after slaughter. The current study determines the levels of five of these proteins in four muscles and how exercise stress changes their abundance. Three of these enzymes, PGK1 (Phosphoglycerate kinase), ENO3 (Beta enolase) and PKM2 (Pyruvate kinase), occur within the glycolysis pathway and other two, glycogen phosphorylase and PGM1 (Phosphoglucomutase), allow the mobilisation of the muscle’s glycogen stores. Four of the enzymes were chosen from literature reports [2] while glycogen phosphorylase was identified by the change in abundance at its molecular mass in SDS-PAGE gels. The longer-term purpose of this work is to find markers of meat quality