Taste-forming mechanisms in single muscle fibers

为明确肌纤维类型对核苷酸含量的影响，测定了牛肌肉、猪肌肉和猪单个肌纤维中核苷酸的浓度。肌苷5′-单磷酸腺苷（IMP）在慢型肌肉中的浓度明显低于快型肌肉，最终pH值在慢型肌肉中较高。结果表明，较高的pH条件加速了慢型肌肉中ATP的降解过程，进而降低了IMP的浓度。测定了从猪腰肌主肌分离的纤维中各单个肌纤维的IMP浓度。虽然从同一大腰肌中分离出慢速型和快速型肌纤维，但慢速型和快速型肌纤维的IMP浓度无显著差异。肌肉解剖中pH值的平衡可以解释肌肉和单个肌纤维结果的冲突。

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.