HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Correspondence: Submit a response Alert me when this article is cited Alert me when Correspondence are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Miranda, A. F. Articles by DiMauro, S. Search for Related Content PubMed PubMed Citation Articles by Miranda, A. F. Articles by DiMauro, S.

Phosphorylase isoenzymes in normal and myophosphorylase-deficient human heart

H. Houston Merritt Clinical Research Center for Muscular Dystrophy and Related Diseases, Departments of Pathology (Drs. Miranda and Nette) and Neurology (Dr. DiMauro), Columbia University College of Physicians and Surgeons, and the Neurological Institute, Presbyterian Hospital, New York, and the Departments of Pediatrics and Neurology, Medical College of Georgia, Augusta, Georgia (Dr. Hartlage).

Address correspondence to Dr. Dilklauro, College of Physicians and Surgeons of Columbia University, 630 West 168 Street, New York, NY 10032.

Phosphorylase isoenzymes were studied by acrylamide-slab electrophoresis in normal tissues and in the heart of a child with a fatal infantile form of myophosphorylase deficiency. Of the three bands present in normal human heart, two were missing in the patient's heart: the slow "muscle" isoenzyme and the intermediate band. Only the fast "cardiac" isoenzyme remained. When extracts of normal skeletal muscle and the patient's heart were mixed in appropriate conditions, the intermediate band reappeared in the electropherogram. Phosphorylase activity in extracts of the patient's heart was not inhibited by antibodies against purified enzyme from mature human muscle, whereas normal human heart phosphorylase was inhibited by approximately 50%. These results suggest that the intermediate band of human heart phosphorylase is a hybrid of skeletal and cardiac muscle isoenzymes. Retained activity of the cardiac isoenzyme may explain why patients genetically lacking skeletal muscle phosphorylase do not have clinical heart disease.

Accepted for publication April 17, 1979.

This article has been cited by other articles:

				E. Gilbert-Barness Metabolic Cardiomyopathy and Conduction System Defects in Children Ann. Clin. Lab. Sci., January 1, 2004; 34(1): 15 - 34. [Abstract] [Full Text] [PDF]

				S. Tsujino, S. Shanske, and S. DiMauro Molecular Genetic Heterogeneity of Myophosphorylase Deficiency (McArdle's Disease) N. Engl. J. Med., July 22, 1993; 329(4): 241 - 245. [Abstract] [Full Text]