Dehydrogenase Enzymes Associated to Glycolysis in Beef Carcasses Stored at 0 °C

After the death of an animal, cell metabolism is controlled locally. The post-mortem oxygen depletion increases the glycolytic activity and lactate production. However, many mechanisms of post-mortem metabolic regulation have not been fully investigated in beef carcasses. In this work, we studied the post-mortem glycolytic behavior (including lactate dehydrogenase) and three dehydrogenase associated to glycolysis (glycerophosphate dehydrogenase, glucose 6-phosphate dehydrogenase, and glycerol dehydrogenase) by using cytochemistry techniques in three fast-twitch muscles (M. longissimus dorsi, M. semimembranosus, and M. cutaneus trunci) of carcasses stored at 0 °C. Our results indicate that glycolysis depends on the type of muscle. The post-mortem glycolytic flux and lactate dehydrogenase activity of M. cutaneus trunci was the lowest of the three muscles studied. Of the other dehydrogenases analyzed, only glycerophosphate and glycerol dehydrogenase showed clear cytochemical reaction. Glucose 6-phosphate dehydrogenase was not used by muscles very much. The glycerophosphate dehydrogenase was the strongest enzymatic activity correlated to the post-mortem glycolytic flux. In addition, a relationship between glycerophosphate dehydrogenase and glycerol dehydrogenase was detected by using a multiple regression model. This phenomenon was studied by using bioinformatics tools, suggesting that glycerophosphate dehydrogenase could oxidize the glycerol in bovine fast-twitch muscles.