The expression of glycogen phosphorylase in normal and dystrophic muscle.
Specific cofactor labelling was employed to determine the degradation rate of glycogen phosphorylase in normal adult C57BL/6J mice and their dystrophic counterparts (C57BL/6Jdy/dy). The rate constant for the decay of phosphorylase-bound label was 0.125 day-1 in normal muscle and 0.49 day-1 in dystrophic muscle, i.e. a lower rate of catabolism of phosphorylase in dystrophic muscle. Quantitative Northern-blot analyses of total RNA isolated from normal and dystrophic muscle indicated that the abundance of phosphorylase mRNA as a percentage of total RNA was approx. 40% lower in dystrophic muscle. The specific activity of phosphorylase in dystrophic muscle is approx. 60% lower than in normal muscle, and is elicited by a lower rate of turnover of the enzyme, i.e. both synthesis and degradation are decreased.
Leyland
D M
DM
Department of Biochemistry, University of Liverpool, U.K.
Beynon
R J
RJ
D000818:Animals; D015152:Blotting, Northern; D005260:Female; D015870:Gene Expression; D007700:Kinetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009132:Muscles / Q000201:enzymology*; D009137:Muscular Dystrophy, Animal / Q000201:enzymology*; D006005:Phosphorylases / Q000235:genetics / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000378:metabolism; D011736:Pyridoxine / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism
D012333:RNA, Messenger; D011732:Pyridoxal Phosphate; D006005:Phosphorylases; D011736:Pyridoxine