Isozymes of AMP-Deaminase in Muscles Myasthenia Gravis Patients

Similar symptoms observed in Myasthenia gravis (MG) can be also detected in the case of skeletal muscle AMP-deaminase deficiency. We compared the activity and expression of AMP-deaminase (AMPD) products in skeletal muscles of MG patients and MG-free individuals. The activity of AMP-deaminase in the muscles of MG patients was significantly higher than in the controls and was 2.05 µmol/min/mg protein (±0.31). The two groups differ in level of AMPD product expression. Furthermore in MG-group molecular size of isoform AMPD1 is 90 kDa in contrast to MG-free group where is present 70 kDa isoform of enzyme. The data suggests that the disturbances in transmission of neuronal signaling, taking place in the skeletal muscles of MG patients, may also change energetic metabolism of the affected muscles by changing molecular mass of isoform.