ENZYMES OF THE PURINE NUCLEOTIDE CYCLE IN MUSCLE OF PATIENTS WITH EXERCISE INTOLERANCE

The activities of adenylosuccinate synthetase, adenylosuccinate lyase, and adenosine monophosphate deaminase were measured in muscle from pa tients suffering from fatigue and cramps following exercise. Results d enote the existence of secundary deficiencies of adenylosuccinate synt hetase and/or adenylosuccinate lyase in subjects with congenital or ac quired myopathies. They also suggest that searches are warranted for p rimary deficiencies of adenylosuccinate synthetase as a cause of exerc ise intolerance. (C) 1998 John Wiley & Sons, Inc.