Taste-forming mechanisms in single muscle fibers

为了阐明肌肉纤维类型对核苷酸含量的影响，测定了牛肌肉、猪肌肉和猪单一肌肉纤维中核苷酸的浓度。慢型肌肉中肌苷5‘-单磷酸(IMP)浓度显著低于快型肌肉，而终末pH值高于快型肌肉。结果表明，较高的pH条件加速了ATP的降解过程，从而降低了慢型肌肉中IMP的浓度。测定了猪腰大肌分离纤维中各肌纤维的IMP浓度，虽然从同一腰大肌分离出慢型和快型肌纤维，但慢型和快型肌纤维的IMP浓度无显著差异。肌肉死后pH的平衡可以解释肌肉和单一肌肉纤维检测结果的冲突。

To clarify the effects of muscle fiber type on the nucleotide content, the concentration of nucleotides were determined from bovine muscles, porcine muscles and porcine single muscle fibers. The concentration of inosine 5'-monophosphate (IMP) was significantly lower in the slow type muscles than that in the fast type muscles, and ultimate pH was higher in the slow type muscles. The results suggested that the higher pH condition accelerated ATP degradation process and then decreased the IMP concentration in the slow type muscles. The IMP concentration of an each single muscle fiber was determined in the fibers separated from porcine psoas major muscles.Although slow and fast type muscle fibers were separated from the same psoas major muscle, there was no significant difference in IMP concentration between the slow and fast muscle fibers. The equilibration of pH in a muscle post-mortem may explain the conflict of the results from muscles and single muscle fibers.