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Increased [ 32 P]‐phosphorylation of tryptic peptides of erythrocyte spectrin in duchenne muscular dystrophy
Author(s) -
Mabry Michael E.,
Roses Allen D.
Publication year - 1981
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880040605
Subject(s) - spectrin , phosphorylation , band 3 , trypsin , chemistry , duchenne muscular dystrophy , peptide , biochemistry , gel electrophoresis , autophosphorylation , microbiology and biotechnology , membrane protein , membrane , biology , protein kinase a , enzyme , cytoskeleton , genetics , cell
Increased [ 32 P]‐incorporation in tryptic peptides of the erythrocyte membrane protein spectrin Band 2 in Duchenne muscular dystrophy (DMD) was studied in a consecutive series of 10 matched DMD/control pairs. Spectrin was [ 32 P]‐phosphorylated by cyclic AMP‐independent endogenous membrane protein kinase in the presence of [γ‐ 32 P]ATP. [ 32 P]‐labeled spectrin was isolated, purified, and subjected to tryptic cleavage with excess trypsin. The resulting peptides were separated on a high‐resolution 5%/15% stacking SDS‐polyacrylamide gel electrophoresis system. Liquid scintillation counting was performed on sequential slices of unstained gels. A broad [ 32 P]‐labeled band containing a number of [ 32 P]‐polypeptides was found to be more highly [ 32 P]‐phosphorylated in DMD patients than in their matched controls. This band migrated with an apparent molecular mass of 4.8–5.2 kilodaltons and contained approximately 55% of total [ 32 P] radioactivity covalently bound to spectrin peptides. These data demonstrated an increased [ 32 P]‐phosphorylation of an identifiable tryptic peptide fraction in DMD that is consistent with previous reports of increased spectrin Band 2 [ 32 P]‐phosphrylation in DMD.