Preclinical increase in activity of muscle microsomal trypsin-like protease in murine muscular dystrophy, C57BL/10-mdx.
Preclinical alterations of protease activities in skeletal muscles from 10-day-old dystrophic mouse, C57BL/10-mdx, were examined by using 10 fluorogenic peptide substrates. Among the activities tested, only Boc-Val-Pro-Arg-MCA-hydrolyzing enzyme of the muscle microsomes showed an about 6-fold higher level of activity in mdx mouse. The increase in activity was not observed in tissues other than skeletal muscle. The enzyme had a pH optimum between 8.5 and 11.0, and was inhibited with DFP and variety of trypsin inhibitors. The enzymatic activity transiently increased at 1-2 weeks of age, the preclinical or very early stage of the disease. These results imply that the increased level of a trypsin-like protease possibly present in muscle microsomes may be closely related to the manifestation of muscular dystrophy.
D000375:Aging; D000818:Animals; D010450:Endopeptidases / Q000378:metabolism*; D007700:Kinetics; D051379:Mice; D008810:Mice, Inbred C57BL; D008861:Microsomes / Q000201:enzymology*; D024510:Muscle Development; D009132:Muscles / Q000201:enzymology*; D009137:Muscular Dystrophy, Animal / Q000201:enzymology*; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D014018:Tissue Distribution; D014357:Trypsin
D010450:Endopeptidases; D014357:Trypsin